diff --git a/sdk/src/main/java/cn/wildfirechat/sdk/Main.java b/sdk/src/main/java/cn/wildfirechat/sdk/Main.java
index 770216e2..ae578073 100644
--- a/sdk/src/main/java/cn/wildfirechat/sdk/Main.java
+++ b/sdk/src/main/java/cn/wildfirechat/sdk/Main.java
@@ -540,7 +540,7 @@ public class Main {
         payload.setType(1);
         payload.setSearchableContent("hello world");
 
-        IMResult<SendMessageResult> resultSendMessage = MessageAdmin.sendMessage("user1", conversation, payload);
+        IMResult<SendMessageResult> resultSendMessage = MessageAdmin.sendMessage("user1", conversation, payload, null);
         if (resultSendMessage != null && resultSendMessage.getErrorCode() == ErrorCode.ERROR_CODE_SUCCESS) {
             System.out.println("send message success");
         } else {
diff --git a/sdk/src/main/java/cn/wildfirechat/sdk/MessageAdmin.java b/sdk/src/main/java/cn/wildfirechat/sdk/MessageAdmin.java
index 6d6a77f4..97bbc40c 100644
--- a/sdk/src/main/java/cn/wildfirechat/sdk/MessageAdmin.java
+++ b/sdk/src/main/java/cn/wildfirechat/sdk/MessageAdmin.java
@@ -8,7 +8,8 @@ import cn.wildfirechat.sdk.utilities.AdminHttpUtils;
 import java.util.List;
 
 public class MessageAdmin {
-    public static IMResult<SendMessageResult> sendMessage(String sender, Conversation conversation, MessagePayload payload) throws Exception {
+    //toUsers为发送给会话中部分用户用的，正常为null，仅当需要指定群/频道/聊天室中部分接收用户时使用
+    public static IMResult<SendMessageResult> sendMessage(String sender, Conversation conversation, MessagePayload payload, List<String> toUsers) throws Exception {
         String path = APIPath.Msg_Send;
         SendMessageData messageData = new SendMessageData();
         messageData.setSender(sender);