diff --git a/README.md b/README.md
index ba21a21..7a969a9 100644
--- a/README.md
+++ b/README.md
@@ -154,6 +154,7 @@ try {
 |v2.0.2|增加敏感信息加密方法(publicEncrypt)|
 |v2.0.3|修复get请求无参时的签名|
 |v2.0.4|修复敏感信息加密方法(publicEncrypt)使用微信平台公钥|
+|v2.0.5|修复发起商家转账零钱参数wx_serial_no(自定义参数，即http请求头Wechatpay-Serial的值)为可选参数|
 
 ## 文档
 [v2支付文档](https://pay.weixin.qq.com/wiki/doc/api/index.html)
diff --git a/docs/batches_transfer.md b/docs/batches_transfer.md
index cc45094..3df3f84 100644
--- a/docs/batches_transfer.md
+++ b/docs/batches_transfer.md
@@ -24,7 +24,7 @@ const res = await pay.batches_transfer({
     batch_remark: '2019年1月深圳分部报销单',
     total_amount: 4000000,
     total_num: 200,
-    wx_serial_no: certificate.serial_no,
+    wx_serial_no: certificate.serial_no, // 当你需要传user_name时 需要传当前参数
     transfer_detail_list: [
       {
         out_detail_no: 'x23zy545Bd5436',
diff --git a/index.ts b/index.ts
index 77e63bd..c90e472 100644
--- a/index.ts
+++ b/index.ts
@@ -689,16 +689,16 @@ class Pay extends Base {
   public async batches_transfer(params: BatchesTransfer.Input): Promise<BatchesTransfer.IOutput> {
     const url = 'https://api.mch.weixin.qq.com/v3/transfer/batches';
     // 请求参数
-    const _params = Object.assign({
+    const _params = {
       appid: this.appid,
       ...params,
-    });
+    };
 
-    const serial_no = _params.wx_serial_no;
+    const serial_no = _params?.wx_serial_no;
     delete _params.wx_serial_no;
     const authorization = this.init('POST', url, _params);
 
-    return await this.postRequestV2(url, _params, authorization, { 'Wechatpay-Serial': serial_no });
+    return await this.postRequestV2(url, _params, authorization, { ...(serial_no && { 'Wechatpay-Serial': serial_no }) });
   }
   /**
    * 微信批次单号查询批次单API
diff --git a/lib/interface-v2.ts b/lib/interface-v2.ts
index 3479a53..f4be77e 100644
--- a/lib/interface-v2.ts
+++ b/lib/interface-v2.ts
@@ -42,8 +42,8 @@ export declare namespace BatchesTransfer {
     total_num: number;
     /** 转账明细列表 */
     transfer_detail_list: TransferDetailList[];
-    /** 微信平台证书序列号 */
-    wx_serial_no: string;
+    /** 微信平台证书序列号-Wechatpay-Serial(当有敏感信息加密时,需要当前参数) */
+    wx_serial_no?: string;
   }
 
   export interface DataOutput {
diff --git a/package.json b/package.json
index ac5b39d..026724c 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "wechatpay-node-v3",
-  "version": "2.0.4",
+  "version": "2.0.5",
   "description": "微信支付文档v3",
   "main": "dist/index.js",
   "types": "dist/index.d.ts",