diff --git a/src/main/java/com/baidu/bjf/remoting/protobuf/ProtobufIDLGenerator.java b/src/main/java/com/baidu/bjf/remoting/protobuf/ProtobufIDLGenerator.java
index 82056a9..91389fd 100644
--- a/src/main/java/com/baidu/bjf/remoting/protobuf/ProtobufIDLGenerator.java
+++ b/src/main/java/com/baidu/bjf/remoting/protobuf/ProtobufIDLGenerator.java
@@ -229,6 +229,12 @@ private static void generateIDL(StringBuilder code, Class<?> cls, Set<Class<?>>
                     isMap = true;
                     Class keyClass = field.getGenericKeyType();
                     Class valueClass = field.getGenericeValueType();
+                    if (keyClass == null) {
+                        keyClass = String.class;
+                    }
+                    if (valueClass == null) {
+                        valueClass = Object.class;
+                    }
                     type = type + "<" + ProtobufProxyUtils.processProtobufType(keyClass) + ", ";
                     type = type + ProtobufProxyUtils.processProtobufType(valueClass) + ">";
 
diff --git a/src/main/java/com/baidu/bjf/remoting/protobuf/utils/ProtobufProxyUtils.java b/src/main/java/com/baidu/bjf/remoting/protobuf/utils/ProtobufProxyUtils.java
index 1fad798..5825936 100644
--- a/src/main/java/com/baidu/bjf/remoting/protobuf/utils/ProtobufProxyUtils.java
+++ b/src/main/java/com/baidu/bjf/remoting/protobuf/utils/ProtobufProxyUtils.java
@@ -209,6 +209,9 @@ public static List<FieldInfo> processDefaultValue(List<Field> fields, boolean ig
                 if (isList) {
                     fieldTypeClass = fieldInfo.getGenericKeyType();
                 }
+                if (fieldTypeClass == null) {
+                    fieldTypeClass = Object.class;
+                }
 
                 FieldType fieldType = TYPE_MAPPING.get(fieldTypeClass);
                 if (fieldType == null) {