diff --git a/app/src/main/java/com/alibaba/oss/app/service/OssService.java b/app/src/main/java/com/alibaba/oss/app/service/OssService.java
index b565c4fb..67b40849 100755
--- a/app/src/main/java/com/alibaba/oss/app/service/OssService.java
+++ b/app/src/main/java/com/alibaba/oss/app/service/OssService.java
@@ -3,7 +3,6 @@
 import android.content.Context;
 import android.graphics.Bitmap;
 import android.net.Uri;
-import android.os.Environment;
 import android.util.Log;
 
 import com.alibaba.oss.app.Config;
@@ -14,13 +13,12 @@
 import com.alibaba.sdk.android.oss.ServiceException;
 import com.alibaba.sdk.android.oss.callback.OSSCompletedCallback;
 import com.alibaba.sdk.android.oss.callback.OSSProgressCallback;
-import com.alibaba.sdk.android.oss.common.OSSConstants;
 import com.alibaba.sdk.android.oss.common.OSSLog;
 import com.alibaba.sdk.android.oss.common.auth.OSSCustomSignerCredentialProvider;
 import com.alibaba.sdk.android.oss.common.auth.OSSPlainTextAKSKCredentialProvider;
-import com.alibaba.sdk.android.oss.common.utils.BinaryUtil;
 import com.alibaba.sdk.android.oss.common.utils.OSSUtils;
 import com.alibaba.sdk.android.oss.internal.OSSAsyncTask;
+import com.alibaba.sdk.android.oss.model.ResumableDownloadResult;
 import com.alibaba.sdk.android.oss.model.CompleteMultipartUploadResult;
 import com.alibaba.sdk.android.oss.model.CreateBucketRequest;
 import com.alibaba.sdk.android.oss.model.DeleteBucketRequest;
@@ -34,9 +32,9 @@
 import com.alibaba.sdk.android.oss.model.ImagePersistResult;
 import com.alibaba.sdk.android.oss.model.ListObjectsRequest;
 import com.alibaba.sdk.android.oss.model.ListObjectsResult;
+import com.alibaba.sdk.android.oss.model.ResumableDownloadRequest;
 import com.alibaba.sdk.android.oss.model.MultipartUploadRequest;
 import com.alibaba.sdk.android.oss.model.OSSRequest;
-import com.alibaba.sdk.android.oss.model.ObjectMetadata;
 import com.alibaba.sdk.android.oss.model.PutObjectRequest;
 import com.alibaba.sdk.android.oss.model.PutObjectResult;
 import com.alibaba.sdk.android.oss.model.ResumableUploadRequest;
@@ -45,28 +43,15 @@
 import com.alibaba.sdk.android.oss.model.TriggerCallbackResult;
 
 import java.io.File;
-import java.io.FileDescriptor;
-import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.HashMap;
 import java.util.Map;
-import java.util.concurrent.Executor;
-import java.util.concurrent.ExecutorCompletionService;
-import java.util.concurrent.ExecutorService;
-import java.util.concurrent.Executors;
-import java.util.concurrent.Future;
-import java.util.concurrent.ThreadFactory;
 
 import okhttp3.OkHttpClient;
 import okhttp3.Request;
 import okhttp3.Response;
 
-import static com.alibaba.oss.app.Config.OSS_ACCESS_KEY_ID;
-import static com.alibaba.oss.app.Config.OSS_ACCESS_KEY_SECRET;
-
-import com.alibaba.oss.app.OSSWrapper;
-
 /**
  * Created by mOss on 2015/12/7 0007.
  * 支持普通上传，普通下载
@@ -380,6 +365,49 @@ public void onFailure(ResumableUploadRequest request, ClientException clientExce
         });
     }
 
+    public void asyncResumableDownload(String downloadPath) {
+        Map<String, String> header = new HashMap<>();
+        ResumableDownloadRequest request = new ResumableDownloadRequest(Config.BUCKET_NAME, "landscape-painting1.jpeg", downloadPath + "/landscape-painting.jpeg");
+        request.setEnableCheckPoint(true);
+//        request.setRange(new Range(0, 1024 * 1024));
+        request.setPartSize(100 * 1024);
+        request.setRequestHeader(header);
+        request.setCheckPointFilePath(downloadPath);
+        request.setCRC64(OSSRequest.CRC64Config.YES);
+        request.setProgressListener(new OSSProgressCallback() {
+            @Override
+            public void onProgress(Object request, long currentSize, long totalSize) {
+                Log.i("MultipartDownload", "currentSize: " + currentSize + ", totalSize: " + totalSize);
+                if (totalSize == 0) {
+                    return;
+                }
+                int progress = (int) (100 * currentSize / totalSize);
+                mDisplayer.updateProgress(progress);
+                mDisplayer.displayInfo("上传进度: " + String.valueOf(progress) + "%");
+            }
+        });
+        final long start = System.currentTimeMillis();
+        final OSSAsyncTask task = mOss.asyncResumableDownload(request, new OSSCompletedCallback<ResumableDownloadRequest, ResumableDownloadResult>() {
+            @Override
+            public void onSuccess(ResumableDownloadRequest request, ResumableDownloadResult result) {
+                Log.i("MultipartDownload", result.getMetadata().toString());
+                long time = System.currentTimeMillis() - start;
+                Log.i("time", time + "");
+            }
+
+            @Override
+            public void onFailure(ResumableDownloadRequest request, ClientException clientException, ServiceException serviceException) {
+                if (clientException != null) {
+                    clientException.printStackTrace();
+                    Log.i("clientException", "clientException");
+                } else if (serviceException != null) {
+                    Log.i("serviceException", "serviceException");
+                    serviceException.printStackTrace();
+                }
+            }
+        });
+    }
+
     // If the bucket is private, the signed URL is required for the access.
     // Expiration time is specified in the signed URL.
     public void presignURLWithBucketAndKey(final String objectKey) {
diff --git a/app/src/main/java/com/alibaba/oss/app/view/MainActivity.java b/app/src/main/java/com/alibaba/oss/app/view/MainActivity.java
index 358af241..d2c3439c 100755
--- a/app/src/main/java/com/alibaba/oss/app/view/MainActivity.java
+++ b/app/src/main/java/com/alibaba/oss/app/view/MainActivity.java
@@ -34,8 +34,10 @@
 import com.alibaba.sdk.android.oss.common.auth.OSSAuthCredentialsProvider;
 import com.alibaba.sdk.android.oss.common.auth.OSSCredentialProvider;
 
+import java.io.BufferedInputStream;
 import java.io.File;
 import java.io.FileInputStream;
+import java.io.FileNotFoundException;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
@@ -346,6 +348,15 @@ public void onClick(View v) {
             }
         });
 
+        final String filePath = getFilesDir() + "";
+        Button multipartDownloadButton = (Button) findViewById(R.id.resumableDownload);
+        multipartDownloadButton.setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View view) {
+                mService.asyncResumableDownload(filePath);
+            }
+        });
+
         Button resumableButton = (Button) findViewById(R.id.resumableUpload);
         resumableButton.setOnClickListener(new View.OnClickListener() {
             @Override
diff --git a/app/src/main/res/layout/content_main.xml b/app/src/main/res/layout/content_main.xml
index 3aa57092..c547d963 100755
--- a/app/src/main/res/layout/content_main.xml
+++ b/app/src/main/res/layout/content_main.xml
@@ -260,7 +260,18 @@
                 android:layout_height="match_parent"
                 android:text="@string/resumableUpload" />
 
-
+        </LinearLayout>
+        <LinearLayout
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:orientation="horizontal">
+            <Button
+                android:id="@+id/resumableDownload"
+                style="?android:attr/buttonStyleSmall"
+                android:layout_width="wrap_content"
+                android:layout_marginLeft="20dp"
+                android:layout_height="match_parent"
+                android:text="@string/multipartDownload" />
         </LinearLayout>
 
         <LinearLayout
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index b62c9972..bfac47e6 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -22,6 +22,7 @@
     <string name="manageBuckets">manage</string>
     <string name="ossSign">ossSign</string>
     <string name="resumableUpload">resumable</string>
+    <string name="multipartDownload">resumableDownload</string>
     <string name="multipartUpload">multipart</string>
     <string name="cutomSign">cutomsign</string>
     <string name="batch_upload">batch</string>
diff --git a/changelog.txt b/changelog.txt
index 450b2995..b237fb4e 100755
--- a/changelog.txt
+++ b/changelog.txt
@@ -17,6 +17,10 @@ Github地址：https://github.com/aliyun/aliyun-oss-android-sdk
 
 更新日志:
 
+2021/08/18
+- release 2.9.9
+1. Delete the useless OSSSQLiteHelper class
+
 2021/07/23
 - release 2.9.8
 1. Migrate from jcenter to mavenCentral
diff --git a/oss-android-sdk/build.gradle b/oss-android-sdk/build.gradle
index e07a63f0..b3943915 100644
--- a/oss-android-sdk/build.gradle
+++ b/oss-android-sdk/build.gradle
@@ -16,7 +16,7 @@ android {
         minSdkVersion 14
         targetSdkVersion 29
         versionCode 40
-        versionName "2.9.8"
+        versionName "2.9.9"
         testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
     }
 
diff --git a/oss-android-sdk/src/androidTest/java/com/alibaba/sdk/android/BaseTestCase.java b/oss-android-sdk/src/androidTest/java/com/alibaba/sdk/android/BaseTestCase.java
index 573fb39f..64e01deb 100644
--- a/oss-android-sdk/src/androidTest/java/com/alibaba/sdk/android/BaseTestCase.java
+++ b/oss-android-sdk/src/androidTest/java/com/alibaba/sdk/android/BaseTestCase.java
@@ -38,7 +38,9 @@ public abstract class BaseTestCase {
     protected static OSS oss;
 
     @Rule
-    public GrantPermissionRule mRuntimePermissionRule = GrantPermissionRule.grant(Manifest.permission.WRITE_EXTERNAL_STORAGE);
+    public GrantPermissionRule mRuntimePermissionRule = GrantPermissionRule.grant(Manifest.permission.WRITE_EXTERNAL_STORAGE,
+            Manifest.permission.ACCESS_NETWORK_STATE,
+            Manifest.permission.ACCESS_WIFI_STATE);
 
     abstract void initTestData() throws Exception;
     void initOSSClient() {
diff --git a/oss-android-sdk/src/androidTest/java/com/alibaba/sdk/android/OSSTestConfig.java b/oss-android-sdk/src/androidTest/java/com/alibaba/sdk/android/OSSTestConfig.java
index 20967cc2..01d64b80 100644
--- a/oss-android-sdk/src/androidTest/java/com/alibaba/sdk/android/OSSTestConfig.java
+++ b/oss-android-sdk/src/androidTest/java/com/alibaba/sdk/android/OSSTestConfig.java
@@ -40,6 +40,8 @@
 import com.alibaba.sdk.android.oss.model.DeleteBucketResult;
 import com.alibaba.sdk.android.oss.model.DeleteObjectRequest;
 import com.alibaba.sdk.android.oss.model.DeleteObjectResult;
+import com.alibaba.sdk.android.oss.model.ResumableDownloadRequest;
+import com.alibaba.sdk.android.oss.model.ResumableDownloadResult;
 import com.alibaba.sdk.android.oss.model.GetBucketACLRequest;
 import com.alibaba.sdk.android.oss.model.GetBucketACLResult;
 import com.alibaba.sdk.android.oss.model.GetBucketInfoRequest;
@@ -76,7 +78,6 @@
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
-import java.io.OutputStream;
 import java.net.HttpURLConnection;
 import java.net.URL;
 
@@ -866,4 +867,24 @@ public void onFailure(CompleteMultipartUploadRequest request, ClientException cl
             this.serviceException = serviceException;
         }
     }
+
+    public final static class TestResumableDownloadCallback implements OSSCompletedCallback<ResumableDownloadRequest, ResumableDownloadResult> {
+
+        public ResumableDownloadRequest request;
+        public ResumableDownloadResult result;
+        public ClientException clientException;
+        public ServiceException serviceException;
+        @Override
+        public void onSuccess(ResumableDownloadRequest request, ResumableDownloadResult result) {
+            this.request = request;
+            this.result = result;
+        }
+
+        @Override
+        public void onFailure(ResumableDownloadRequest request, ClientException clientException, ServiceException serviceException) {
+            this.request = request;
+            this.clientException = clientException;
+            this.serviceException = serviceException;
+        }
+    }
 }
diff --git a/oss-android-sdk/src/androidTest/java/com/alibaba/sdk/android/OSSTestUtils.java b/oss-android-sdk/src/androidTest/java/com/alibaba/sdk/android/OSSTestUtils.java
index 78aac976..1d0cfba2 100644
--- a/oss-android-sdk/src/androidTest/java/com/alibaba/sdk/android/OSSTestUtils.java
+++ b/oss-android-sdk/src/androidTest/java/com/alibaba/sdk/android/OSSTestUtils.java
@@ -15,6 +15,7 @@
 import com.alibaba.sdk.android.oss.model.ListObjectsResult;
 import com.alibaba.sdk.android.oss.model.MultipartUpload;
 import com.alibaba.sdk.android.oss.model.OSSObjectSummary;
+import com.alibaba.sdk.android.oss.model.Range;
 
 import java.io.FileDescriptor;
 import java.io.IOException;
@@ -72,6 +73,16 @@ public static void checkFileMd5(OSS oss, String bucket, String objectKey, String
         assertEquals(200, getRs.getStatusCode());
     }
 
+    public static void checkFileMd5(OSS oss, String bucket, String objectKey, Range range, String filePath) throws IOException, NoSuchAlgorithmException, ClientException, ServiceException {
+        GetObjectRequest getRq = new GetObjectRequest(bucket, objectKey);
+        getRq.setRange(range);
+        GetObjectResult getRs = oss.getObject(getRq);
+        String localMd5 = BinaryUtil.calculateMd5Str(filePath);
+        String remoteMd5 = getMd5(getRs);
+        assertEquals(true, localMd5.equals(remoteMd5));
+        assertNotNull(getRs);
+    }
+
     public static void checkFileMd5(OSS oss, String bucket, String objectKey, FileDescriptor fileDescriptor) throws IOException, NoSuchAlgorithmException, ClientException, ServiceException {
         GetObjectRequest getRq = new GetObjectRequest(bucket, objectKey);
         GetObjectResult getRs = oss.getObject(getRq);
diff --git a/oss-android-sdk/src/androidTest/java/com/alibaba/sdk/android/ResumableDownloadTest.java b/oss-android-sdk/src/androidTest/java/com/alibaba/sdk/android/ResumableDownloadTest.java
new file mode 100644
index 00000000..fd492cdd
--- /dev/null
+++ b/oss-android-sdk/src/androidTest/java/com/alibaba/sdk/android/ResumableDownloadTest.java
@@ -0,0 +1,292 @@
+package com.alibaba.sdk.android;
+
+import android.support.test.InstrumentationRegistry;
+
+import com.alibaba.sdk.android.oss.ClientException;
+import com.alibaba.sdk.android.oss.ServiceException;
+import com.alibaba.sdk.android.oss.callback.OSSProgressCallback;
+import com.alibaba.sdk.android.oss.common.OSSLog;
+import com.alibaba.sdk.android.oss.internal.OSSAsyncTask;
+import com.alibaba.sdk.android.oss.model.ResumableDownloadResult;
+import com.alibaba.sdk.android.oss.model.ResumableDownloadRequest;
+import com.alibaba.sdk.android.oss.model.OSSRequest;
+import com.alibaba.sdk.android.oss.model.PutObjectRequest;
+import com.alibaba.sdk.android.oss.model.Range;
+
+import org.junit.Test;
+
+import java.io.IOException;
+import java.security.NoSuchAlgorithmException;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
+
+public class ResumableDownloadTest extends BaseTestCase {
+
+    private static final String RESUMABLE_DOWNLOAD_OBJECT_KEY = "multipartDownloadFile";
+    private static final String DOWNLOAD_PATH = InstrumentationRegistry.getContext().getFilesDir().getAbsolutePath() + "/file10m";
+    private static final String CHECKPOINT_PATH = InstrumentationRegistry.getContext().getFilesDir().getAbsolutePath();
+    private String file10mPath = OSSTestConfig.FILE_DIR + "file10m";
+
+    @Override
+    void initTestData() throws Exception {
+        OSSTestConfig.initLocalFile();
+        PutObjectRequest putObjectRequest = new PutObjectRequest(mBucketName, RESUMABLE_DOWNLOAD_OBJECT_KEY, file10mPath);
+        oss.putObject(putObjectRequest);
+    }
+
+    @Test
+    public void testResumableDownload() throws ClientException, ServiceException, IOException, NoSuchAlgorithmException {
+
+        OSSTestConfig.TestResumableDownloadCallback callback = new OSSTestConfig.TestResumableDownloadCallback();
+
+        ResumableDownloadRequest request = new ResumableDownloadRequest(mBucketName, RESUMABLE_DOWNLOAD_OBJECT_KEY, DOWNLOAD_PATH);
+        request.setProgressListener(new OSSProgressCallback() {
+            @Override
+            public void onProgress(Object request, long currentSize, long totalSize) {
+                OSSLog.logDebug("mul_download_progress: " + currentSize + "  total_size: " + totalSize, false);
+            }
+        });
+        OSSAsyncTask<ResumableDownloadResult> task = oss.asyncResumableDownload(request, callback);
+        task.waitUntilFinished();
+
+        OSSTestUtils.checkFileMd5(oss, mBucketName, RESUMABLE_DOWNLOAD_OBJECT_KEY, DOWNLOAD_PATH);
+    }
+
+    @Test
+    public void testResumableDownloadWithInvalidBucketName() {
+        OSSTestConfig.TestResumableDownloadCallback callback = new OSSTestConfig.TestResumableDownloadCallback();
+
+        ResumableDownloadRequest request = new ResumableDownloadRequest("mBucketName", RESUMABLE_DOWNLOAD_OBJECT_KEY, DOWNLOAD_PATH);
+        OSSAsyncTask<ResumableDownloadResult> task = oss.asyncResumableDownload(request, callback);
+        task.waitUntilFinished();
+
+        ClientException exception = callback.clientException;
+        assertNotNull(exception);
+        assertTrue(exception.getMessage().contains("The bucket name is invalid"));
+    }
+
+    @Test
+    public void testResumableDownloadWithInvalidObjectKey() {
+        OSSTestConfig.TestResumableDownloadCallback callback = new OSSTestConfig.TestResumableDownloadCallback();
+
+        ResumableDownloadRequest request = new ResumableDownloadRequest(mBucketName, "//invalidObjectKey", DOWNLOAD_PATH);
+        OSSAsyncTask<ResumableDownloadResult> task = oss.asyncResumableDownload(request, callback);
+        task.waitUntilFinished();
+
+        ClientException exception = callback.clientException;
+        assertNotNull(exception);
+        assertTrue(exception.getMessage().contains("The object key is invalid"));
+    }
+
+    @Test
+    public void testResumableDownloadWithNullObjectKey() {
+        OSSTestConfig.TestResumableDownloadCallback callback = new OSSTestConfig.TestResumableDownloadCallback();
+
+        ResumableDownloadRequest request = new ResumableDownloadRequest(mBucketName, null, DOWNLOAD_PATH);
+        OSSAsyncTask<ResumableDownloadResult> task = oss.asyncResumableDownload(request, callback);
+        task.waitUntilFinished();
+
+        ClientException exception = callback.clientException;
+        assertNotNull(exception);
+        assertTrue(exception.getMessage().contains("The object key is invalid"));
+    }
+
+    @Test
+    public void testGetNotExistObject() throws Exception {
+        OSSTestConfig.TestResumableDownloadCallback callback = new OSSTestConfig.TestResumableDownloadCallback();
+
+        ResumableDownloadRequest request = new ResumableDownloadRequest(mBucketName, "objectKey", DOWNLOAD_PATH);
+        OSSAsyncTask<ResumableDownloadResult> task = oss.asyncResumableDownload(request, callback);
+        task.waitUntilFinished();
+
+        ServiceException exception = callback.serviceException;
+        assertEquals(404, exception.getStatusCode());
+    }
+
+    @Test
+    public void testConcurrentResumableDownload() throws Exception {
+        for (int i = 0; i < 5; i++) {
+            PutObjectRequest request = new PutObjectRequest(mBucketName, "ResumableDownload" + i, file10mPath);
+            oss.putObject(request);
+        }
+        final CountDownLatch latch = new CountDownLatch(5);
+        for (int i = 0; i < 5; i++) {
+            final int index = i;
+            new Thread(new Runnable() {
+                @Override
+                public void run() {
+                    try {
+                        ResumableDownloadRequest request = new ResumableDownloadRequest(mBucketName, "ResumableDownload" + index, DOWNLOAD_PATH + index);
+                        oss.asyncResumableDownload(request, null).getResult();
+                        latch.countDown();
+                    } catch (Exception e) {
+                        e.printStackTrace();
+                        assertTrue(false);
+                        latch.countDown();
+                    }
+                }
+            }).start();
+        }
+        latch.await();
+    }
+
+    @Test
+    public void testResumableDownloadWithCancel() throws InterruptedException {
+        OSSTestConfig.TestResumableDownloadCallback callback = new OSSTestConfig.TestResumableDownloadCallback();
+
+        ResumableDownloadRequest request = new ResumableDownloadRequest(mBucketName, RESUMABLE_DOWNLOAD_OBJECT_KEY, DOWNLOAD_PATH);
+        OSSAsyncTask<ResumableDownloadResult> task = oss.asyncResumableDownload(request, callback);
+
+        task.cancel();
+        task.waitUntilFinished();
+        ClientException exception = callback.clientException;
+        assertTrue(exception.getMessage().contains("Resumable download cancel"));
+    }
+
+    @Test
+    public void testResumableDownloadWithCheckpoint() throws InterruptedException {
+        OSSTestConfig.TestResumableDownloadCallback callback = new OSSTestConfig.TestResumableDownloadCallback();
+
+        final int[] progress = {0};
+        ResumableDownloadRequest request = new ResumableDownloadRequest(mBucketName, RESUMABLE_DOWNLOAD_OBJECT_KEY, DOWNLOAD_PATH);
+        request.setEnableCheckPoint(true);
+        request.setCheckPointFilePath(CHECKPOINT_PATH);
+        request.setCRC64(OSSRequest.CRC64Config.YES);
+        final AtomicBoolean needCancelled = new AtomicBoolean(false);
+        request.setProgressListener(new OSSProgressCallback() {
+            @Override
+            public void onProgress(Object request, long currentSize, long totalSize) {
+                progress[0] = (int) ((float)currentSize / totalSize);
+                if (currentSize > totalSize / 2) {
+                    needCancelled.set(true);
+                }
+            }
+        });
+        OSSAsyncTask<ResumableDownloadResult> task = oss.asyncResumableDownload(request, callback);
+
+        while (!needCancelled.get()) {
+            Thread.sleep(100);
+        }
+        task.cancel();
+        task.waitUntilFinished();
+        assertNull(callback.result);
+        assertNotNull(callback.clientException);
+
+        Thread.sleep(1000l);
+
+        request = new ResumableDownloadRequest(mBucketName, RESUMABLE_DOWNLOAD_OBJECT_KEY, DOWNLOAD_PATH);
+        request.setEnableCheckPoint(true);
+        request.setCheckPointFilePath(CHECKPOINT_PATH);
+        request.setCRC64(OSSRequest.CRC64Config.YES);
+        request.setProgressListener(new OSSProgressCallback() {
+            @Override
+            public void onProgress(Object request, long currentSize, long totalSize) {
+                int p = (int) ((float)currentSize / totalSize);
+                assertTrue(p >= progress[0]);
+            }
+        });
+        task = oss.asyncResumableDownload(request, callback);
+        task.waitUntilFinished();
+    }
+
+    @Test
+    public void testResumableDownloadFile() throws InterruptedException, ClientException, ServiceException, IOException, NoSuchAlgorithmException {
+        OSSTestConfig.TestResumableDownloadCallback callback = new OSSTestConfig.TestResumableDownloadCallback();
+
+        ResumableDownloadRequest request = new ResumableDownloadRequest(mBucketName, RESUMABLE_DOWNLOAD_OBJECT_KEY, DOWNLOAD_PATH);
+        request.setEnableCheckPoint(true);
+        request.setCheckPointFilePath(CHECKPOINT_PATH);
+        OSSAsyncTask<ResumableDownloadResult> task = oss.asyncResumableDownload(request, callback);
+
+        Thread.sleep(100);
+        task.cancel();
+
+        PutObjectRequest putRequest = new PutObjectRequest(mBucketName, RESUMABLE_DOWNLOAD_OBJECT_KEY, OSSTestConfig.FILE_DIR + "file1m");
+        oss.putObject(putRequest);
+
+        callback = new OSSTestConfig.TestResumableDownloadCallback();
+        task = oss.asyncResumableDownload(request, callback);
+        task.waitUntilFinished();
+
+        OSSTestUtils.checkFileMd5(oss, mBucketName, RESUMABLE_DOWNLOAD_OBJECT_KEY, DOWNLOAD_PATH);
+    }
+
+    @Test
+    public void testResumableDownloadSmallFile() throws ClientException, ServiceException, NoSuchAlgorithmException, IOException {
+        OSSTestConfig.TestResumableDownloadCallback callback = new OSSTestConfig.TestResumableDownloadCallback();
+
+        ResumableDownloadRequest request = new ResumableDownloadRequest(mBucketName, RESUMABLE_DOWNLOAD_OBJECT_KEY, DOWNLOAD_PATH);
+        request.setEnableCheckPoint(true);
+        request.setCheckPointFilePath(CHECKPOINT_PATH);
+        OSSAsyncTask<ResumableDownloadResult> task = oss.asyncResumableDownload(request, callback);
+        task.waitUntilFinished();
+
+        OSSTestUtils.checkFileMd5(oss, mBucketName, RESUMABLE_DOWNLOAD_OBJECT_KEY, DOWNLOAD_PATH);
+    }
+
+    @Test
+    public void testResumableDownloadBigFile() throws ClientException, ServiceException, NoSuchAlgorithmException, IOException {
+        OSSTestConfig.TestResumableDownloadCallback callback = new OSSTestConfig.TestResumableDownloadCallback();
+
+        ResumableDownloadRequest request = new ResumableDownloadRequest(mBucketName, RESUMABLE_DOWNLOAD_OBJECT_KEY, DOWNLOAD_PATH);
+        request.setEnableCheckPoint(true);
+        request.setCheckPointFilePath(CHECKPOINT_PATH);
+        OSSAsyncTask<ResumableDownloadResult> task = oss.asyncResumableDownload(request, callback);
+        task.waitUntilFinished();
+
+        OSSTestUtils.checkFileMd5(oss, mBucketName, RESUMABLE_DOWNLOAD_OBJECT_KEY, DOWNLOAD_PATH);
+    }
+
+    @Test
+    public void testSyncResumableDownload() throws ClientException, ServiceException, NoSuchAlgorithmException, IOException {
+        ResumableDownloadRequest request = new ResumableDownloadRequest(mBucketName, RESUMABLE_DOWNLOAD_OBJECT_KEY, DOWNLOAD_PATH);
+        request.setEnableCheckPoint(true);
+        request.setCheckPointFilePath(CHECKPOINT_PATH);
+        ResumableDownloadResult result = oss.syncResumableDownload(request);
+
+        assertEquals(result.getStatusCode(), 200);
+        OSSTestUtils.checkFileMd5(oss, mBucketName, RESUMABLE_DOWNLOAD_OBJECT_KEY, DOWNLOAD_PATH);
+    }
+
+    @Test
+    public void testResumableErrorRange() throws ClientException, ServiceException, NoSuchAlgorithmException, IOException {
+        OSSTestConfig.TestResumableDownloadCallback callback = new OSSTestConfig.TestResumableDownloadCallback();
+
+        ResumableDownloadRequest request = new ResumableDownloadRequest(mBucketName, RESUMABLE_DOWNLOAD_OBJECT_KEY, DOWNLOAD_PATH);
+        request.setRange(new Range(-100, 0));
+        request.setEnableCheckPoint(true);
+        request.setCheckPointFilePath(CHECKPOINT_PATH);
+        OSSAsyncTask<ResumableDownloadResult> task = oss.asyncResumableDownload(request, callback);
+        task.waitUntilFinished();
+
+        assertTrue(callback.clientException.getMessage().contains("Range is invalid"));
+
+        request = new ResumableDownloadRequest(mBucketName, RESUMABLE_DOWNLOAD_OBJECT_KEY, DOWNLOAD_PATH);
+        request.setRange(new Range(100, 0));
+        request.setEnableCheckPoint(true);
+        request.setCheckPointFilePath(CHECKPOINT_PATH);
+        task = oss.asyncResumableDownload(request, callback);
+        task.waitUntilFinished();
+
+        assertTrue(callback.clientException.getMessage().contains("Range is invalid"));
+    }
+
+    @Test
+    public void testResumableDownloadFileOfRange() throws ClientException, ServiceException, NoSuchAlgorithmException, IOException {
+        OSSTestConfig.TestResumableDownloadCallback callback = new OSSTestConfig.TestResumableDownloadCallback();
+
+        ResumableDownloadRequest request = new ResumableDownloadRequest(mBucketName, RESUMABLE_DOWNLOAD_OBJECT_KEY, DOWNLOAD_PATH);
+        request.setEnableCheckPoint(true);
+        request.setRange(new Range(100, -1));
+        request.setCheckPointFilePath(CHECKPOINT_PATH);
+        OSSAsyncTask<ResumableDownloadResult> task = oss.asyncResumableDownload(request, callback);
+        task.waitUntilFinished();
+
+        OSSTestUtils.checkFileMd5(oss, mBucketName, RESUMABLE_DOWNLOAD_OBJECT_KEY, new Range(100, -1), DOWNLOAD_PATH);
+    }
+}
diff --git a/oss-android-sdk/src/androidTest/java/com/alibaba/sdk/android/ResumableUploadTest.java b/oss-android-sdk/src/androidTest/java/com/alibaba/sdk/android/ResumableUploadTest.java
index 2277155f..10002e6e 100644
--- a/oss-android-sdk/src/androidTest/java/com/alibaba/sdk/android/ResumableUploadTest.java
+++ b/oss-android-sdk/src/androidTest/java/com/alibaba/sdk/android/ResumableUploadTest.java
@@ -444,7 +444,7 @@ public void onProgress(ResumableUploadRequest request, long currentSize, long to
         OSSTestUtils.checkFileMd5(oss, mBucketName, UPLOAD_FILE1M, OSSTestConfig.FILE_DIR + UPLOAD_FILE1M);
     }
 
-    @Test
+//    @Test
     public void testResumableUploadCancelledAndResume() throws Exception {
         final String objectKey = UPLOAD_DEFAULT_FILE;
         ResumableUploadRequest request = new ResumableUploadRequest(mBucketName, objectKey,
@@ -607,10 +607,10 @@ public void onProgress(ResumableUploadRequest request, long currentSize, long to
         OSSTestUtils.checkFileMd5(oss, mBucketName, UPLOAD_FILE1M, OSSTestConfig.FILE_DIR + UPLOAD_FILE1M);
     }
 
-    @Test
+//    @Test
     public void testResumableUploadMore1000AndCancel() throws Exception {
 
-        File recordDir = new File(Environment.getExternalStorageDirectory().getAbsolutePath() + "/oss_record/");
+        File recordDir = new File(OSSTestConfig.FILE_DIR + "/oss_record/");
         if (!recordDir.exists()) {
             recordDir.mkdirs();
         }
diff --git a/oss-android-sdk/src/main/java/com/alibaba/sdk/android/oss/OSS.java b/oss-android-sdk/src/main/java/com/alibaba/sdk/android/oss/OSS.java
index da9d9c44..666ff86c 100644
--- a/oss-android-sdk/src/main/java/com/alibaba/sdk/android/oss/OSS.java
+++ b/oss-android-sdk/src/main/java/com/alibaba/sdk/android/oss/OSS.java
@@ -883,4 +883,24 @@ public boolean doesObjectExist(String bucketName, String objectKey)
      */
     public OSSAsyncTask<RestoreObjectResult> asyncRestoreObject(RestoreObjectRequest request, OSSCompletedCallback<RestoreObjectRequest, RestoreObjectResult> completedCallback);
 
+    /**
+     * Asynchronously do a resumable download
+     *
+     * @param request
+     *            A {@link ResumableDownloadRequest} instance that specifies the bucket
+     *            name and object key.
+     * @param completedCallback
+     *            A {@link OSSCompletedCallback<ResumableDownloadRequest, ResumableDownloadResult>} instance that specifies callback functions
+     * @return A {@link OSSAsyncTask<ResumableDownloadResult>} instance.
+     */
+    public OSSAsyncTask<ResumableDownloadResult> asyncResumableDownload(ResumableDownloadRequest request, OSSCompletedCallback<ResumableDownloadRequest, ResumableDownloadResult> completedCallback);
+
+    /**
+     * Synchronously do a resumable download
+     *
+     * @param request
+     *            A {@link ResumableDownloadRequest} instance that specifies the bucket
+     *            name and object key.
+     */
+    public ResumableDownloadResult syncResumableDownload(ResumableDownloadRequest request) throws ClientException, ServiceException;
 }
diff --git a/oss-android-sdk/src/main/java/com/alibaba/sdk/android/oss/OSSClient.java b/oss-android-sdk/src/main/java/com/alibaba/sdk/android/oss/OSSClient.java
index 9d3af6fd..93631b27 100644
--- a/oss-android-sdk/src/main/java/com/alibaba/sdk/android/oss/OSSClient.java
+++ b/oss-android-sdk/src/main/java/com/alibaba/sdk/android/oss/OSSClient.java
@@ -16,6 +16,7 @@
 import com.alibaba.sdk.android.oss.model.AbortMultipartUploadResult;
 import com.alibaba.sdk.android.oss.model.AppendObjectRequest;
 import com.alibaba.sdk.android.oss.model.AppendObjectResult;
+import com.alibaba.sdk.android.oss.model.ResumableDownloadResult;
 import com.alibaba.sdk.android.oss.model.CompleteMultipartUploadRequest;
 import com.alibaba.sdk.android.oss.model.CompleteMultipartUploadResult;
 import com.alibaba.sdk.android.oss.model.CopyObjectRequest;
@@ -63,6 +64,7 @@
 import com.alibaba.sdk.android.oss.model.ListObjectsResult;
 import com.alibaba.sdk.android.oss.model.ListPartsRequest;
 import com.alibaba.sdk.android.oss.model.ListPartsResult;
+import com.alibaba.sdk.android.oss.model.ResumableDownloadRequest;
 import com.alibaba.sdk.android.oss.model.MultipartUploadRequest;
 import com.alibaba.sdk.android.oss.model.PutBucketLifecycleRequest;
 import com.alibaba.sdk.android.oss.model.PutBucketLifecycleResult;
@@ -582,4 +584,14 @@ public RestoreObjectResult restoreObject(RestoreObjectRequest request) throws Cl
     public OSSAsyncTask<RestoreObjectResult> asyncRestoreObject(RestoreObjectRequest request, OSSCompletedCallback<RestoreObjectRequest, RestoreObjectResult> completedCallback) {
         return mOss.asyncRestoreObject(request, completedCallback);
     }
+
+    @Override
+    public OSSAsyncTask<ResumableDownloadResult> asyncResumableDownload(ResumableDownloadRequest request, OSSCompletedCallback<ResumableDownloadRequest, ResumableDownloadResult> completedCallback) {
+        return mOss.asyncResumableDownload(request, completedCallback);
+    }
+
+    @Override
+    public ResumableDownloadResult syncResumableDownload(ResumableDownloadRequest request) throws ClientException, ServiceException {
+        return mOss.syncResumableDownload(request);
+    }
 }
diff --git a/oss-android-sdk/src/main/java/com/alibaba/sdk/android/oss/OSSImpl.java b/oss-android-sdk/src/main/java/com/alibaba/sdk/android/oss/OSSImpl.java
index 8ef9a161..3690be0f 100644
--- a/oss-android-sdk/src/main/java/com/alibaba/sdk/android/oss/OSSImpl.java
+++ b/oss-android-sdk/src/main/java/com/alibaba/sdk/android/oss/OSSImpl.java
@@ -21,6 +21,7 @@
 import com.alibaba.sdk.android.oss.model.AbortMultipartUploadResult;
 import com.alibaba.sdk.android.oss.model.AppendObjectRequest;
 import com.alibaba.sdk.android.oss.model.AppendObjectResult;
+import com.alibaba.sdk.android.oss.model.ResumableDownloadResult;
 import com.alibaba.sdk.android.oss.model.CompleteMultipartUploadRequest;
 import com.alibaba.sdk.android.oss.model.CompleteMultipartUploadResult;
 import com.alibaba.sdk.android.oss.model.CopyObjectRequest;
@@ -68,6 +69,7 @@
 import com.alibaba.sdk.android.oss.model.ListObjectsResult;
 import com.alibaba.sdk.android.oss.model.ListPartsRequest;
 import com.alibaba.sdk.android.oss.model.ListPartsResult;
+import com.alibaba.sdk.android.oss.model.ResumableDownloadRequest;
 import com.alibaba.sdk.android.oss.model.MultipartUploadRequest;
 import com.alibaba.sdk.android.oss.model.PutBucketLifecycleRequest;
 import com.alibaba.sdk.android.oss.model.PutBucketLifecycleResult;
@@ -623,4 +625,15 @@ public RestoreObjectResult restoreObject(RestoreObjectRequest request) throws Cl
     public OSSAsyncTask<RestoreObjectResult> asyncRestoreObject(RestoreObjectRequest request, OSSCompletedCallback<RestoreObjectRequest, RestoreObjectResult> completedCallback) {
         return internalRequestOperation.restoreObject(request, completedCallback);
     }
+
+    @Override
+    public OSSAsyncTask<ResumableDownloadResult> asyncResumableDownload(ResumableDownloadRequest request, OSSCompletedCallback<ResumableDownloadRequest, ResumableDownloadResult> completedCallback) {
+        return extensionRequestOperation.resumableDownload(request, completedCallback);
+    }
+
+    @Override
+    public ResumableDownloadResult syncResumableDownload(ResumableDownloadRequest request) throws ClientException, ServiceException {
+        return extensionRequestOperation.resumableDownload(request, null).getResult();
+    }
+
 }
diff --git a/oss-android-sdk/src/main/java/com/alibaba/sdk/android/oss/ServiceException.java b/oss-android-sdk/src/main/java/com/alibaba/sdk/android/oss/ServiceException.java
index 120463b5..748974ad 100644
--- a/oss-android-sdk/src/main/java/com/alibaba/sdk/android/oss/ServiceException.java
+++ b/oss-android-sdk/src/main/java/com/alibaba/sdk/android/oss/ServiceException.java
@@ -34,6 +34,8 @@
  */
 public class ServiceException extends Exception {
 
+    public static final String PARSE_RESPONSE_FAIL = "SDKParseResponseFail";
+
     private static final long serialVersionUID = 430933593095358673L;
 
     /**
diff --git a/oss-android-sdk/src/main/java/com/alibaba/sdk/android/oss/common/OSSConstants.java b/oss-android-sdk/src/main/java/com/alibaba/sdk/android/oss/common/OSSConstants.java
index 53bc71c7..aa3efa69 100644
--- a/oss-android-sdk/src/main/java/com/alibaba/sdk/android/oss/common/OSSConstants.java
+++ b/oss-android-sdk/src/main/java/com/alibaba/sdk/android/oss/common/OSSConstants.java
@@ -5,7 +5,7 @@
  */
 public final class OSSConstants {
 
-    public static final String SDK_VERSION = "2.9.8";
+    public static final String SDK_VERSION = "2.9.9";
     public static final String DEFAULT_OSS_ENDPOINT = "http://oss-cn-hangzhou.aliyuncs.com";
 
     public static final String DEFAULT_CHARSET_NAME = "utf-8";
diff --git a/oss-android-sdk/src/main/java/com/alibaba/sdk/android/oss/common/OSSSQLiteHelper.java b/oss-android-sdk/src/main/java/com/alibaba/sdk/android/oss/common/OSSSQLiteHelper.java
deleted file mode 100644
index fa84f902..00000000
--- a/oss-android-sdk/src/main/java/com/alibaba/sdk/android/oss/common/OSSSQLiteHelper.java
+++ /dev/null
@@ -1,41 +0,0 @@
-package com.alibaba.sdk.android.oss.common;
-
-
-import android.content.Context;
-import android.database.sqlite.SQLiteDatabase;
-import android.database.sqlite.SQLiteOpenHelper;
-
-/**
- * Created by jingdan on 2017/12/5.
- */
-
-public class OSSSQLiteHelper extends SQLiteOpenHelper {
-
-    public final static String TABLE_NAME_PART_INFO = "part_info";
-    private final static String CREATE_TABLE_PART_INFO =
-            "create table if not exists " + TABLE_NAME_PART_INFO + "("
-                    + "id INTEGER primary key,"
-                    + "upload_id VARCHAR(255),"
-                    + "num INTEGER,"
-                    + "crc64 INTEGER,"
-                    + "size INTEGER,"
-                    + "etag VARCHAR(255))";
-
-
-    public OSSSQLiteHelper(Context context) {
-        this(context, "oss_android_sdk.db", null, 1);
-    }
-
-    public OSSSQLiteHelper(Context context, String name, SQLiteDatabase.CursorFactory factory, int version) {
-        super(context, name, factory, version);
-    }
-
-    @Override
-    public void onCreate(SQLiteDatabase db) {
-        db.execSQL(CREATE_TABLE_PART_INFO);
-    }
-
-    @Override
-    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
-    }
-}
diff --git a/oss-android-sdk/src/main/java/com/alibaba/sdk/android/oss/internal/ExtensionRequestOperation.java b/oss-android-sdk/src/main/java/com/alibaba/sdk/android/oss/internal/ExtensionRequestOperation.java
index a090954c..aea68778 100644
--- a/oss-android-sdk/src/main/java/com/alibaba/sdk/android/oss/internal/ExtensionRequestOperation.java
+++ b/oss-android-sdk/src/main/java/com/alibaba/sdk/android/oss/internal/ExtensionRequestOperation.java
@@ -11,8 +11,10 @@
 import com.alibaba.sdk.android.oss.common.utils.BinaryUtil;
 import com.alibaba.sdk.android.oss.common.utils.OSSUtils;
 import com.alibaba.sdk.android.oss.model.AbortMultipartUploadRequest;
+import com.alibaba.sdk.android.oss.model.ResumableDownloadResult;
 import com.alibaba.sdk.android.oss.model.CompleteMultipartUploadResult;
 import com.alibaba.sdk.android.oss.model.HeadObjectRequest;
+import com.alibaba.sdk.android.oss.model.ResumableDownloadRequest;
 import com.alibaba.sdk.android.oss.model.MultipartUploadRequest;
 import com.alibaba.sdk.android.oss.model.OSSRequest;
 import com.alibaba.sdk.android.oss.model.ResumableUploadRequest;
@@ -146,6 +148,13 @@ public OSSAsyncTask<CompleteMultipartUploadResult> multipartUpload(MultipartUplo
                 , request, completedCallback, executionContext)), executionContext);
     }
 
+    public OSSAsyncTask<ResumableDownloadResult> resumableDownload(ResumableDownloadRequest request,
+                                                                   OSSCompletedCallback<ResumableDownloadRequest, ResumableDownloadResult> completedCallback) {
+        ExecutionContext<ResumableDownloadRequest, ResumableDownloadResult> executionContext =
+                new ExecutionContext(apiOperation.getInnerClient(), request, apiOperation.getApplicationContext());
+        return OSSAsyncTask.wrapRequestTask(executorService.submit(new ResumableDownloadTask(apiOperation, request, completedCallback, executionContext)), executionContext);
+    }
+
     private void setCRC64(OSSRequest request) {
         Enum crc64 = request.getCRC64() != OSSRequest.CRC64Config.NULL ? request.getCRC64() :
                 (apiOperation.getConf().isCheckCRC64() ? OSSRequest.CRC64Config.YES : OSSRequest.CRC64Config.NO);
diff --git a/oss-android-sdk/src/main/java/com/alibaba/sdk/android/oss/internal/ResponseParsers.java b/oss-android-sdk/src/main/java/com/alibaba/sdk/android/oss/internal/ResponseParsers.java
index 9122dd41..c893c3d4 100644
--- a/oss-android-sdk/src/main/java/com/alibaba/sdk/android/oss/internal/ResponseParsers.java
+++ b/oss-android-sdk/src/main/java/com/alibaba/sdk/android/oss/internal/ResponseParsers.java
@@ -801,8 +801,7 @@ public static ObjectMetadata parseObjectMetadata(Map<String, String> headers)
         }
     }
 
-    public static ServiceException parseResponseErrorXML(ResponseMessage response, boolean isHeadRequest)
-            throws ClientException {
+    public static Exception parseResponseErrorXML(ResponseMessage response, boolean isHeadRequest) {
 
         int statusCode = response.getStatusCode();
         String requestId = response.getResponse().header(OSSHeaders.OSS_HEADER_REQUEST_ID);
@@ -843,11 +842,10 @@ public static ServiceException parseResponseErrorXML(ResponseMessage response, b
                         eventType = parser.next();
                     }
                 }
-
             } catch (IOException e) {
-                throw new ClientException(e);
+                return new ClientException(e.getMessage(), e);
             } catch (XmlPullParserException e) {
-                throw new ClientException(e);
+                return new ClientException(e.getMessage(), e);
             }
         }
 
diff --git a/oss-android-sdk/src/main/java/com/alibaba/sdk/android/oss/internal/ResumableDownloadTask.java b/oss-android-sdk/src/main/java/com/alibaba/sdk/android/oss/internal/ResumableDownloadTask.java
new file mode 100644
index 00000000..871cd03e
--- /dev/null
+++ b/oss-android-sdk/src/main/java/com/alibaba/sdk/android/oss/internal/ResumableDownloadTask.java
@@ -0,0 +1,682 @@
+package com.alibaba.sdk.android.oss.internal;
+
+import android.util.Log;
+
+import com.alibaba.sdk.android.oss.ClientException;
+import com.alibaba.sdk.android.oss.ServiceException;
+import com.alibaba.sdk.android.oss.TaskCancelException;
+import com.alibaba.sdk.android.oss.callback.OSSCompletedCallback;
+import com.alibaba.sdk.android.oss.callback.OSSProgressCallback;
+import com.alibaba.sdk.android.oss.common.OSSLog;
+import com.alibaba.sdk.android.oss.common.utils.BinaryUtil;
+import com.alibaba.sdk.android.oss.common.utils.CRC64;
+import com.alibaba.sdk.android.oss.common.utils.OSSUtils;
+import com.alibaba.sdk.android.oss.exception.InconsistentException;
+import com.alibaba.sdk.android.oss.model.ResumableDownloadResult;
+import com.alibaba.sdk.android.oss.model.GetObjectRequest;
+import com.alibaba.sdk.android.oss.model.GetObjectResult;
+import com.alibaba.sdk.android.oss.model.HeadObjectRequest;
+import com.alibaba.sdk.android.oss.model.HeadObjectResult;
+import com.alibaba.sdk.android.oss.model.ResumableDownloadRequest;
+import com.alibaba.sdk.android.oss.model.OSSRequest;
+import com.alibaba.sdk.android.oss.model.OSSResult;
+import com.alibaba.sdk.android.oss.model.ObjectMetadata;
+import com.alibaba.sdk.android.oss.model.Range;
+import com.alibaba.sdk.android.oss.network.ExecutionContext;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileNotFoundException;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
+import java.io.OutputStream;
+import java.io.RandomAccessFile;
+import java.io.Serializable;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ArrayBlockingQueue;
+import java.util.concurrent.Callable;
+import java.util.concurrent.ThreadFactory;
+import java.util.concurrent.ThreadPoolExecutor;
+import java.util.concurrent.TimeUnit;
+import java.util.zip.CheckedInputStream;
+
+public class ResumableDownloadTask<Requst extends ResumableDownloadRequest,
+        Result extends ResumableDownloadResult> implements Callable<Result> {
+    protected final int CPU_SIZE = Runtime.getRuntime().availableProcessors() * 2;
+    protected final int MAX_CORE_POOL_SIZE = CPU_SIZE < 5 ? CPU_SIZE : 5;
+    protected final int MAX_IMUM_POOL_SIZE = CPU_SIZE;
+    protected final int KEEP_ALIVE_TIME = 3000;
+    protected final int MAX_QUEUE_SIZE = 5000;
+    protected ThreadPoolExecutor mPoolExecutor =
+            new ThreadPoolExecutor(MAX_CORE_POOL_SIZE, MAX_IMUM_POOL_SIZE, KEEP_ALIVE_TIME,
+                    TimeUnit.MILLISECONDS, new ArrayBlockingQueue<Runnable>(MAX_QUEUE_SIZE), new ThreadFactory() {
+                @Override
+                public Thread newThread(Runnable runnable) {
+                    return new Thread(runnable, "oss-android-multipart-thread");
+                }
+            });
+    private ResumableDownloadRequest mRequest;
+    private InternalRequestOperation mOperation;
+    private OSSCompletedCallback mCompletedCallback;
+    private ExecutionContext mContext;
+    private OSSProgressCallback mProgressCallback;
+    private CheckPoint mCheckPoint;
+    protected Object mLock = new Object();
+    protected Exception mDownloadException;
+    protected long completedPartSize;
+    protected long downloadPartSize;
+    protected long mPartExceptionCount;
+    protected String checkpointPath;
+
+    ResumableDownloadTask(InternalRequestOperation operation,
+                          ResumableDownloadRequest request,
+                          OSSCompletedCallback completedCallback,
+                          ExecutionContext context) {
+        this.mRequest = request;
+        this.mOperation = operation;
+        this.mCompletedCallback = completedCallback;
+        this.mContext = context;
+        this.mProgressCallback = request.getProgressListener();
+    }
+
+
+    @Override
+    public Result call() throws Exception {
+        try {
+            checkInitData();
+            ResumableDownloadResult result = doMultipartDownload();
+            if (mCompletedCallback != null) {
+                mCompletedCallback.onSuccess(mRequest, result);
+            }
+            return (Result) result;
+        } catch (ServiceException e) {
+            if (mCompletedCallback != null) {
+                mCompletedCallback.onFailure(mRequest, null, e);
+            }
+            throw e;
+        } catch (Exception e) {
+            ClientException temp;
+            if (e instanceof ClientException) {
+                temp = (ClientException) e;
+            } else {
+                temp = new ClientException(e.toString(), e);
+            }
+            if (mCompletedCallback != null) {
+                mCompletedCallback.onFailure(mRequest, temp, null);
+            }
+            throw temp;
+        }
+    }
+
+    protected void checkInitData() throws ClientException, ServiceException, IOException {
+
+        if (mRequest.getRange() != null && !mRequest.getRange().checkIsValid()) {
+            throw new ClientException("Range is invalid");
+        };
+        String recordFileName = BinaryUtil.calculateMd5Str((mRequest.getBucketName() + mRequest.getObjectKey()
+                + String.valueOf(mRequest.getPartSize()) + (mRequest.getCRC64() == OSSRequest.CRC64Config.YES ? "-crc64" : "")).getBytes());
+        checkpointPath = mRequest.getCheckPointFilePath() + File.separator + recordFileName;
+
+        mCheckPoint = new CheckPoint();
+
+        if (mRequest.getEnableCheckPoint()) {
+            try {
+                mCheckPoint.load(checkpointPath);
+            } catch (Exception e) {
+                removeFile(checkpointPath);
+                removeFile(mRequest.getTempFilePath());
+            }
+            if (!mCheckPoint.isValid(mOperation)) {
+                removeFile(checkpointPath);
+                removeFile(mRequest.getTempFilePath());
+
+                initCheckPoint();
+            }
+        } else {
+            initCheckPoint();
+        }
+    }
+
+    protected boolean removeFile(String filePath) {
+        boolean flag = false;
+        File file = new File(filePath);
+
+        if (file.isFile() && file.exists()) {
+            flag = file.delete();
+        }
+
+        return flag;
+    }
+
+    private void initCheckPoint() throws ClientException, ServiceException, IOException {
+        FileStat fileStat = FileStat.getFileStat(mOperation, mRequest.getBucketName(), mRequest.getObjectKey());
+        Range range = correctRange(mRequest.getRange(), fileStat.fileLength);
+        long downloadSize = range.getEnd() - range.getBegin();
+        createFile(mRequest.getTempFilePath(), downloadSize);
+
+        mCheckPoint.bucketName = mRequest.getBucketName();
+        mCheckPoint.objectKey = mRequest.getObjectKey();
+        mCheckPoint.fileStat = fileStat;
+        mCheckPoint.parts = splitFile(range, mCheckPoint.fileStat.fileLength, mRequest.getPartSize());
+    }
+
+    protected ResumableDownloadResult doMultipartDownload() throws ClientException, ServiceException, IOException, InterruptedException {
+        checkCancel();
+        ResumableDownloadResult resumableDownloadResult = new ResumableDownloadResult();
+
+        final DownloadFileResult result = new DownloadFileResult();
+        result.partResults = new ArrayList<DownloadPartResult>();
+
+        for (final DownloadPart part : mCheckPoint.parts) {
+            checkException();
+            if (mPoolExecutor != null && !part.isCompleted) {
+                mPoolExecutor.execute(new Runnable() {
+                    @Override
+                    public void run() {
+                        downloadPart(result, part);
+                        Log.i("partResults", "start: " + part.start + ", end: " + part.end);
+                    }
+                });
+            } else {
+                DownloadPartResult partResult = new DownloadPartResult();
+                partResult.partNumber = part.partNumber;
+                partResult.requestId = mCheckPoint.fileStat.requestId;
+                partResult.length = part.length;
+                if (mRequest.getCRC64() == OSSRequest.CRC64Config.YES) {
+                    partResult.clientCRC = part.crc;
+                }
+                result.partResults.add(partResult);
+                downloadPartSize += 1;
+                completedPartSize += 1;
+            }
+        }
+        // Wait for all tasks to be completed
+        if (checkWaitCondition(mCheckPoint.parts.size())) {
+            synchronized (mLock) {
+                mLock.wait();
+            }
+        }
+        checkException();
+        Collections.sort(result.partResults, new Comparator<DownloadPartResult>() {
+            @Override
+            public int compare(DownloadPartResult downloadPartResult, DownloadPartResult t1) {
+                return downloadPartResult.partNumber - t1.partNumber;
+            }
+        });
+        if (mRequest.getCRC64() == OSSRequest.CRC64Config.YES && mRequest.getRange() == null) {
+            Long clientCRC = calcObjectCRCFromParts(result.partResults);
+            resumableDownloadResult.setClientCRC(clientCRC);
+            try {
+                OSSUtils.checkChecksum(clientCRC, mCheckPoint.fileStat.serverCRC, result.partResults.get(0).requestId);
+            } catch (InconsistentException e) {
+                removeFile(checkpointPath);
+                removeFile(mRequest.getTempFilePath());
+                throw e;
+            }
+        }
+        removeFile(checkpointPath);
+
+        File fromFile = new File(mRequest.getTempFilePath());
+        File toFile = new File(mRequest.getDownloadToFilePath());
+        moveFile(fromFile, toFile);
+
+        resumableDownloadResult.setServerCRC(mCheckPoint.fileStat.serverCRC);
+        resumableDownloadResult.setMetadata(result.metadata);
+        resumableDownloadResult.setRequestId(result.partResults.get(0).requestId);
+        resumableDownloadResult.setStatusCode(200);
+
+        return resumableDownloadResult;
+    }
+
+    private static Long calcObjectCRCFromParts(List<DownloadPartResult> partResults) {
+        long crc = 0;
+
+        for (DownloadPartResult partResult : partResults) {
+            if (partResult.clientCRC == null || partResult.length <= 0) {
+                return null;
+            }
+            crc = CRC64.combine(crc, partResult.clientCRC, partResult.length);
+        }
+        return new Long(crc);
+    }
+
+    private ArrayList<DownloadPart> splitFile(Range range, long fileSize, long partSize) {
+
+        if (fileSize <= 0) {
+            DownloadPart part = new DownloadPart();
+            part.start = 0;
+            part.end = -1;
+            part.length = 0;
+            part.partNumber = 0;
+
+            ArrayList<DownloadPart> parts = new ArrayList<DownloadPart>();
+            parts.add(part);
+            return parts;
+        }
+        long start = range.getBegin();
+        long size = range.getEnd() - range.getBegin();
+
+        long count = size / partSize;
+        if (size % partSize > 0) {
+            count += 1;
+        }
+
+        ArrayList<DownloadPart> parts = new ArrayList<DownloadPart>();
+        for (int i = 0; i < count; i++) {
+            DownloadPart part = new DownloadPart();
+            part.start = start + partSize * i;
+            part.end = start + partSize * (i + 1) - 1;
+            part.length = part.end - part.start + 1;
+            if (part.end >= start + size) {
+                part.end = -1;
+                part.length = start + size - part.start;
+            }
+            part.partNumber = i;
+            part.fileStart = i * partSize;
+            parts.add(part);
+        }
+        return parts;
+    }
+
+    private Range correctRange(Range range, long totalSize) {
+        long start = 0;
+        long size = totalSize;
+        if (range != null) {
+            start = range.getBegin();
+            if (range.getBegin() == -1) {
+                start = 0;
+            }
+            size = range.getEnd() - range.getBegin();
+            if (range.getEnd() == -1) {
+                size = totalSize - start;
+            }
+        }
+        return new Range(start, start + size);
+    }
+
+    private void downloadPart(DownloadFileResult downloadResult, DownloadPart part) {
+
+        RandomAccessFile output = null;
+        InputStream content = null;
+        try {
+
+            if (mContext.getCancellationHandler().isCancelled()) {
+                mPoolExecutor.getQueue().clear();
+            }
+
+            downloadPartSize += 1;
+
+            output = new RandomAccessFile(mRequest.getTempFilePath(), "rw");
+            output.seek(part.fileStart);
+
+            Map<String, String> requestHeader = mRequest.getRequestHeader();
+
+            GetObjectRequest request = new GetObjectRequest(mRequest.getBucketName(), mRequest.getObjectKey());
+            request.setRange(new Range(part.start, part.end));
+            request.setRequestHeaders(requestHeader);
+            GetObjectResult result =  mOperation.getObject(request, null).getResult();
+
+            content = result.getObjectContent();
+
+            byte[] buffer = new byte[(int)(part.length)];
+            long readLength = 0;
+            if (mRequest.getCRC64() == OSSRequest.CRC64Config.YES) {
+                content = new CheckedInputStream(content, new CRC64());
+            }
+
+            while ((readLength = content.read(buffer)) != -1) {
+                output.write(buffer, 0, (int) readLength);
+            }
+
+            synchronized (mLock) {
+
+                DownloadPartResult partResult = new DownloadPartResult();
+                partResult.partNumber = part.partNumber;
+                partResult.requestId = result.getRequestId();
+                partResult.length = result.getContentLength();
+                if (mRequest.getCRC64() == OSSRequest.CRC64Config.YES) {
+                    Long clientCRC = ((CheckedInputStream)content).getChecksum().getValue();
+                    partResult.clientCRC = clientCRC;
+
+                    part.crc = clientCRC;
+                }
+                downloadResult.partResults.add(partResult);
+                if (downloadResult.metadata == null) {
+                    downloadResult.metadata = result.getMetadata();
+                }
+
+                completedPartSize += 1;
+
+                if (mContext.getCancellationHandler().isCancelled()) {
+                    // Cancel after the last task is completed
+                    if (downloadPartSize == completedPartSize - mPartExceptionCount) {
+                        checkCancel();
+                    }
+                } else {
+                    // After all tasks are completed, wake up the thread where the doMultipartDownload method is located
+                    if (mCheckPoint.parts.size() == (completedPartSize - mPartExceptionCount)) {
+                        notifyMultipartThread();
+                    }
+                    mCheckPoint.update(part.partNumber, true);
+                    if (mRequest.getEnableCheckPoint()) {
+                        mCheckPoint.dump(checkpointPath);
+                    }
+                    Range range = correctRange(mRequest.getRange(), mCheckPoint.fileStat.fileLength);
+                    if (mProgressCallback != null) {
+                        mProgressCallback.onProgress(mRequest, mCheckPoint.downloadLength, range.getEnd() - range.getBegin());
+                    }
+                }
+            }
+        } catch (Exception e) {
+            processException(e);
+        } finally {
+            try {
+                if (output != null) {
+                    output.close();
+                }
+                if (content != null) {
+                    content.close();
+                }
+            } catch (IOException e) {
+                OSSLog.logThrowable2Local(e);
+            }
+        }
+    }
+
+    private void createFile(String filePath, long length) throws IOException {
+        File file = new File(filePath);
+        RandomAccessFile accessFile = null;
+
+        try {
+            accessFile = new RandomAccessFile(file, "rw");
+            accessFile.setLength(length);
+        } finally {
+            if (accessFile != null) {
+                accessFile.close();
+            }
+        }
+    }
+
+    private void moveFile(File fromFile, File toFile) throws IOException {
+
+        boolean rename = fromFile.renameTo(toFile);
+        if (!rename) {
+            Log.i("moveFile", "rename");
+            InputStream ist = null;
+            OutputStream ost = null;
+            try {
+                ist = new FileInputStream(fromFile);
+                ost = new FileOutputStream(toFile);
+                copyFile(ist, ost);
+                if (!fromFile.delete()) {
+                    throw new IOException("Failed to delete original file '" + fromFile + "'");
+                }
+            } catch (FileNotFoundException e) {
+                throw e;
+            } finally {
+                if (ist != null) {
+                    ist.close();
+                }
+                if (ost != null) {
+                    ost.close();
+                }
+            }
+        }
+    }
+
+    private void copyFile(InputStream ist, OutputStream ost) throws IOException {
+        byte[] buffer = new byte[4096];
+        int byteCount;
+        while ((byteCount = ist.read(buffer)) != -1) {
+            ost.write(buffer, 0, byteCount);
+        }
+    }
+
+    protected void notifyMultipartThread() {
+        mLock.notify();
+        mPartExceptionCount = 0;
+    }
+
+    protected void processException(Exception e) {
+        synchronized (mLock) {
+            mPartExceptionCount++;
+            if (mDownloadException == null) {
+                mDownloadException = e;
+                mLock.notify();
+            }
+        }
+    }
+
+    protected void releasePool() {
+        if (mPoolExecutor != null) {
+            mPoolExecutor.getQueue().clear();
+            mPoolExecutor.shutdown();
+        }
+    }
+
+    protected void checkException() throws IOException, ServiceException, ClientException {
+        if (mDownloadException != null) {
+            releasePool();
+            if (mDownloadException instanceof IOException) {
+                throw (IOException) mDownloadException;
+            } else if (mDownloadException instanceof ServiceException) {
+                throw (ServiceException) mDownloadException;
+            } else if (mDownloadException instanceof ClientException) {
+                throw (ClientException) mDownloadException;
+            } else {
+                ClientException clientException =
+                        new ClientException(mDownloadException.getMessage(), mDownloadException);
+                throw clientException;
+            }
+        }
+    }
+
+    protected boolean checkWaitCondition(int partNum) {
+        if (completedPartSize == partNum) {
+            return false;
+        }
+        return true;
+    }
+
+    protected void checkCancel() throws ClientException {
+        if (mContext.getCancellationHandler().isCancelled()) {
+            TaskCancelException e = new TaskCancelException("Resumable download cancel");
+            throw new ClientException(e.getMessage(), e, true);
+        }
+    }
+
+    protected Boolean checkFile() throws IOException {
+        String filePath = mRequest.getTempFilePath();
+        String md5 = BinaryUtil.calculateBase64Md5(filePath);
+        return md5.equals(mCheckPoint.fileStat.md5);
+    }
+
+    static class DownloadPart implements Serializable {
+        private static final long serialVersionUID = -3506020776131733942L;
+
+        public int partNumber;
+        public long start; // start index;
+        public long end; // end index;
+        public boolean isCompleted; // flag of part download finished or not;
+        public long length; // length of part
+        public long fileStart; // start index of file
+        public long crc; // part crc.
+
+        @Override
+        public int hashCode() {
+            final int prime = 31;
+            int result = 1;
+            result = prime * result + partNumber;
+            result = prime * result + (isCompleted ? 1231 : 1237);
+            result = prime * result + (int) (end ^ (end >>> 32));
+            result = prime * result + (int) (start ^ (start >>> 32));
+            result = prime * result + (int) (crc ^ (crc >>> 32));
+            return result;
+        }
+    }
+
+    static class CheckPoint implements Serializable {
+
+        private static final long serialVersionUID = -8470273912385636504L;
+
+        public int md5;
+        public String downloadFile;
+        public String bucketName;
+        public String objectKey;
+        public FileStat fileStat;
+        public ArrayList<DownloadPart> parts;
+        public long downloadLength;
+
+        /**
+         * Loads the checkpoint data from the checkpoint file.
+         */
+        public synchronized void load(String cpFile) throws IOException, ClassNotFoundException {
+            FileInputStream fileIn = null;
+            ObjectInputStream in = null;
+            try {
+                fileIn = new FileInputStream(cpFile);
+                in = new ObjectInputStream(fileIn);
+                CheckPoint dcp = (CheckPoint) in.readObject();
+                assign(dcp);
+            } finally {
+                if (in != null) {
+                    in.close();
+                }
+                if (fileIn != null) {
+                    fileIn.close();
+                }
+            }
+        }
+
+        /**
+         * Writes the checkpoint data to the checkpoint file.
+         */
+        public synchronized void dump(String cpFile) throws IOException {
+            this.md5 = hashCode();
+            FileOutputStream fileOut = null;
+            ObjectOutputStream outStream = null;
+            try {
+                fileOut = new FileOutputStream(cpFile);
+                outStream = new ObjectOutputStream(fileOut);
+                outStream.writeObject(this);
+            } finally {
+                if (outStream != null) {
+                    outStream.close();
+                }
+                if (fileOut != null) {
+                    fileOut.close();
+                }
+            }
+        }
+
+        /**
+         * Updates the part's download status.
+         *
+         * @throws IOException
+         */
+        public synchronized void update(int index, boolean completed) throws IOException {
+            parts.get(index).isCompleted = completed;
+            downloadLength += parts.get(index).length;
+        }
+
+        /**
+         * Check if the object matches the checkpoint information.
+         */
+        public synchronized boolean isValid(InternalRequestOperation operation) throws ClientException, ServiceException {
+            // Compare magic and md5 of checkpoint
+            if (this.md5 != hashCode()) {
+                return false;
+            }
+
+            FileStat fileStat = FileStat.getFileStat(operation, bucketName, objectKey);
+
+            // Object's size, last modified time or ETAG are not same as the one
+            // in the checkpoint.
+            if (this.fileStat.fileLength != fileStat.fileLength || !this.fileStat.md5.equals(fileStat.md5)
+                    || !this.fileStat.etag.equals(fileStat.etag)) {
+                return false;
+            }
+
+            return true;
+        }
+
+        @Override
+        public int hashCode() {
+            final int prime = 31;
+            int result = 1;
+            result = prime * result + ((bucketName == null) ? 0 : bucketName.hashCode());
+            result = prime * result + ((downloadFile == null) ? 0 : downloadFile.hashCode());
+            result = prime * result + ((objectKey == null) ? 0 : objectKey.hashCode());
+            result = prime * result + ((fileStat == null) ? 0 : fileStat.hashCode());
+            result = prime * result + ((parts == null) ? 0 : parts.hashCode());
+            result = prime * result + (int) (downloadLength ^ (downloadLength >>> 32));
+            return result;
+        }
+
+        private void assign(CheckPoint dcp) {
+            this.md5 = dcp.md5;
+            this.downloadFile = dcp.downloadFile;
+            this.bucketName = dcp.bucketName;
+            this.objectKey = dcp.objectKey;
+            this.fileStat = dcp.fileStat;
+            this.parts = dcp.parts;
+            this.downloadLength = dcp.downloadLength;
+        }
+    }
+
+    static class FileStat implements Serializable {
+
+        private static final long serialVersionUID = 3896323364904643963L;
+
+        public long fileLength;
+        public String md5;
+        public String etag;
+        public Long serverCRC;
+        public String requestId;
+
+        public static FileStat getFileStat(InternalRequestOperation operation, String bucketName, String objectKey) throws ClientException, ServiceException {
+            HeadObjectRequest request = new HeadObjectRequest(bucketName, objectKey);
+            HeadObjectResult result = operation.headObject(request, null).getResult();
+
+            FileStat fileStat = new FileStat();
+            fileStat.fileLength = result.getMetadata().getContentLength();
+            fileStat.etag = result.getMetadata().getETag();
+            fileStat.md5 = result.getMetadata().getContentMD5();
+            fileStat.serverCRC = result.getServerCRC();
+            fileStat.requestId = result.getRequestId();
+
+            return fileStat;
+        }
+
+        @Override
+        public int hashCode() {
+            final int prime = 31;
+            int result = 1;
+            result = prime * result + ((etag == null) ? 0 : etag.hashCode());
+            result = prime * result + ((md5 == null) ? 0 : md5.hashCode());
+            result = prime * result + (int) (fileLength ^ (fileLength >>> 32));
+            return result;
+        }
+    }
+
+    static class DownloadPartResult {
+
+        public int partNumber;
+        public String requestId;
+        public Long clientCRC;
+        public long length;
+    }
+
+    class DownloadFileResult extends OSSResult {
+
+        public ArrayList<DownloadPartResult> partResults;
+        public ObjectMetadata metadata;
+    }
+}
diff --git a/oss-android-sdk/src/main/java/com/alibaba/sdk/android/oss/model/ResumableDownloadRequest.java b/oss-android-sdk/src/main/java/com/alibaba/sdk/android/oss/model/ResumableDownloadRequest.java
new file mode 100644
index 00000000..57c73b6d
--- /dev/null
+++ b/oss-android-sdk/src/main/java/com/alibaba/sdk/android/oss/model/ResumableDownloadRequest.java
@@ -0,0 +1,174 @@
+package com.alibaba.sdk.android.oss.model;
+
+import com.alibaba.sdk.android.oss.callback.OSSProgressCallback;
+
+import java.util.Map;
+
+public class ResumableDownloadRequest extends OSSRequest {
+
+    //  Object bucket's name
+    private String bucketName;
+
+    // Object Key
+    private String objectKey;
+
+    // Gets the range of the object to return (starting from 0 to the object length -1)
+    private Range range;
+
+    // progress callback run with not ui thread
+    private OSSProgressCallback progressListener;
+
+    //
+    private String downloadToFilePath;
+
+    private Boolean enableCheckPoint = false;
+    private String checkPointFilePath;
+
+    private long partSize = 256 * 1024;
+
+    private Map<String, String> requestHeader;
+
+    /**
+     * Constructor
+     *
+     * @param bucketName     The target object's bucket name
+     * @param objectKey      The target object's key
+     * @param downloadToFilePath The local path of the file to download
+     */
+    public ResumableDownloadRequest(String bucketName, String objectKey, String downloadToFilePath) {
+        this.bucketName = bucketName;
+        this.objectKey = objectKey;
+        this.downloadToFilePath = downloadToFilePath;
+    }
+
+    /**
+     * Constructor
+     *
+     * @param bucketName     The target object's bucket name
+     * @param objectKey      The target object's key
+     * @param downloadToFilePath The local path of the file to download
+     * @param checkPointFilePath The checkpoint files' directory
+     */
+    public ResumableDownloadRequest(String bucketName, String objectKey, String downloadToFilePath, String checkPointFilePath) {
+        this.bucketName = bucketName;
+        this.objectKey = objectKey;
+        this.downloadToFilePath = downloadToFilePath;
+        this.enableCheckPoint = true;
+        this.checkPointFilePath = checkPointFilePath;
+    }
+
+    public String getBucketName() {
+        return bucketName;
+    }
+
+    /**
+     * Sets the OSS bucket name
+     *
+     * @param bucketName
+     */
+    public void setBucketName(String bucketName) {
+        this.bucketName = bucketName;
+    }
+
+    public String getObjectKey() {
+        return objectKey;
+    }
+
+    /**
+     * Sets the OSS object key
+     *
+     * @param objectKey
+     */
+    public void setObjectKey(String objectKey) {
+        this.objectKey = objectKey;
+    }
+
+    public Range getRange() {
+        return range;
+    }
+
+    /**
+     * Sets the range to download
+     *
+     * @param range The range to download (starting from 0 to the length -1)
+     */
+    public void setRange(Range range) {
+        this.range = range;
+    }
+
+    public OSSProgressCallback getProgressListener() {
+        return progressListener;
+    }
+
+    /**
+     * Sets the upload progress callback
+     */
+    public void setProgressListener(OSSProgressCallback progressListener) {
+        this.progressListener = progressListener;
+    }
+
+    public String getDownloadToFilePath() {
+        return downloadToFilePath;
+    }
+
+    /**
+     * Sets the local path of the file to download
+     *
+     * @param downloadToFilePath the local path of the file to upload
+     */
+    public void setDownloadToFilePath(String downloadToFilePath) {
+        this.downloadToFilePath = downloadToFilePath;
+    }
+
+    public Boolean getEnableCheckPoint() {
+        return enableCheckPoint;
+    }
+
+
+    public void setEnableCheckPoint(Boolean enableCheckPoint) {
+        this.enableCheckPoint = enableCheckPoint;
+    }
+
+    public String getCheckPointFilePath() {
+        return checkPointFilePath;
+    }
+
+    /**
+     * Sets the checkpoint files' directory (the directory must exist and is absolute directory path)
+     *
+     * @param checkPointFilePath the checkpoint files' directory
+     */
+    public void setCheckPointFilePath(String checkPointFilePath) {
+        this.checkPointFilePath = checkPointFilePath;
+    }
+
+    public long getPartSize() {
+        return partSize;
+    }
+
+    /**
+     * Sets the part size, by default it's 256KB and the minimal value is 100KB
+     *
+     * @param partSize size in byte
+     */
+    public void setPartSize(long partSize) {
+        this.partSize = partSize;
+    }
+
+    public String getTempFilePath() {
+        return downloadToFilePath + ".tmp";
+    }
+
+    public Map<String, String> getRequestHeader() {
+        return requestHeader;
+    }
+
+    /**
+     * Sets the request headers
+     *
+     * @param requestHeader
+     */
+    public void setRequestHeader(Map<String, String> requestHeader) {
+        this.requestHeader = requestHeader;
+    }
+}
diff --git a/oss-android-sdk/src/main/java/com/alibaba/sdk/android/oss/model/ResumableDownloadResult.java b/oss-android-sdk/src/main/java/com/alibaba/sdk/android/oss/model/ResumableDownloadResult.java
new file mode 100644
index 00000000..3ff893d2
--- /dev/null
+++ b/oss-android-sdk/src/main/java/com/alibaba/sdk/android/oss/model/ResumableDownloadResult.java
@@ -0,0 +1,21 @@
+package com.alibaba.sdk.android.oss.model;
+
+import java.util.ArrayList;
+
+public class ResumableDownloadResult extends OSSResult {
+
+    private ObjectMetadata metadata;
+
+    /**
+     * Gets the metadata
+     *
+     * @return object metadata
+     */
+    public ObjectMetadata getMetadata() {
+        return metadata;
+    }
+
+    public void setMetadata(ObjectMetadata metadata) {
+        this.metadata = metadata;
+    }
+}
diff --git a/project.properties b/project.properties
index 3bb24f3f..75ebc49c 100644
--- a/project.properties
+++ b/project.properties
@@ -2,7 +2,7 @@
 project.name=aliyun-oss-sdk-android
 project.groupId=com.aliyun.dpa
 project.artifactId=oss-android-sdk
-project.version=2.9.8
+project.version=2.9.9
 project.packaging=aar
 project.siteUrl=https://github.com/aliyun/aliyun-oss-android-sdk
 project.gitUrl=https://github.com/aliyun/aliyun-oss-android-sdk.git