diff --git a/astrbot/core/platform/sources/aiocqhttp/aiocqhttp_platform_adapter.py b/astrbot/core/platform/sources/aiocqhttp/aiocqhttp_platform_adapter.py
index 525869980..0a2e8d430 100644
--- a/astrbot/core/platform/sources/aiocqhttp/aiocqhttp_platform_adapter.py
+++ b/astrbot/core/platform/sources/aiocqhttp/aiocqhttp_platform_adapter.py
@@ -140,7 +140,7 @@ class AiocqhttpAdapter(Platform):
             abm.type = MessageType.FRIEND_MESSAGE
         if self.unique_session and abm.type == MessageType.GROUP_MESSAGE:
             abm.session_id = (
-                abm.sender.user_id + "_" + str(event.group_id)
+                str(abm.sender.user_id) + "_" + str(event.group_id)
             )  # 也保留群组 id
         else:
             abm.session_id = (