diff --git a/examples/farm_ai_demo/tos_farm_ai_config.h b/examples/farm_ai_demo/tos_farm_ai_config.h
index af2678b0..335e43f9 100644
--- a/examples/farm_ai_demo/tos_farm_ai_config.h
+++ b/examples/farm_ai_demo/tos_farm_ai_config.h
@@ -1,5 +1,5 @@
 #ifndef _H_TOS_FARM_AI_CONFIG_H  
-#define  _H_TOS_FARM_AI_CONFIG_H
+#define _H_TOS_FARM_AI_CONFIG_H
 
 #define MQTT_SERVER_IP          "iotcloud-mqtt.gz.tencentdevices.com"
 #define MQTT_SERVER_PORT        "1883"