diff --git a/edu_coder/mqtt_client.py b/edu_coder/mqtt_client.py
index a7e8ddb..241d557 100644
--- a/edu_coder/mqtt_client.py
+++ b/edu_coder/mqtt_client.py
@@ -2,8 +2,8 @@ import paho.mqtt.client as mqtt
 import time
 import os
 
-# 全局变量，用于标记是否收到响应
-os.system("bash get_user.sh")
+if os.path.exists("user.txt"):
+    os.system("bash get_user.sh")
 
 broker = '121.40.129.71'
 port = 48835