diff --git a/MQTT.py b/MQTT.py
index 6168895..e333e58 100644
--- a/MQTT.py
+++ b/MQTT.py
@@ -5,9 +5,7 @@ import paho.mqtt.client as mqtt
 
 from tool import push_stream, close_stream, update, exec_sh, get_record, get_list_record, get_status
 
-import os
 
-device_name = os.getenv('device_name')
 
 
 def on_connect(client, userdata, flags, rc):
@@ -16,6 +14,8 @@ def on_connect(client, userdata, flags, rc):
 
 
 def valid(msg, client):
+    import os
+    device_name = os.getenv('device_name')
     origin_data = json.loads(msg.payload.decode('utf-8'))
     if 'msg' not in origin_data:
         client.publish('error', payload='msg must be supplied', qos=0)