Aiming at problems such as missing and false alarms that may be caused by the complex drawer structure due to its irregular structure, small area for installing sensor modules, and many monitoring nodes. This paper designs a concentration gradient algorithm that accurately locates the leakage point.Through the experimental test, it is proved that the whole monitoring system can work normally in the environment of - 15 ℃ to 55 ℃.The false alarm rate of the system is less than 3% and the missing alarm rate is less than 1%, which verifies the stability and practicability of the whole system.In other similar complex drawer structures with the risk of gas or liquid leakage, such as chemical industry, agriculture, medicine, military, environmental protection and other specific scenarios, this technology meets the needs of a wide range of universal testing.