diff --git a/handler/tool.go b/handler/tool.go
index 3c938ad..27d6a49 100644
--- a/handler/tool.go
+++ b/handler/tool.go
@@ -209,6 +209,7 @@ func subscribeAndHandleMessagesV6(ws *websocket.Conn, deviceId int) {
 				worker.SetRedisSetRemove(online_conn_key, con_id)
 				break
 			}
+			buf = nil
 			c = count
 		} else {
 			//每秒发送一次心跳检测