Abstract: In connection with the application of TCS in the leak detection of underground fuel pipeline network in the parking apron of new Guangzhou Baiyun International Airport, this paper discusses leak detection method and implementation scheme for fuel pipeline network in the parking apron of civil airport. TCS system uses pressure step method to detect leak. Its basic principle is that two different pressure values are continuously added to the closed pipe section until it reaches the two relatively high and low pressure values set in advance. Through the comparison of curves of pipe section pressure value under different pressure, the "leakage coefficient" can be worked out, which can then help to judge the leakage. This system is applicable to the constructed pipeline because the cost of installation and renovation is low, detection time is short at only 50 min, and the detection precision is high, reaching 0.04 L/(h·m³).