A new type of testing platform which could be used to detect different types of automobile clutch master cylinder sealing with programmable logic controller(PLC) as control unit and differential pressure transducer for real time detection of pressure was developed to improve the accuracy,precision and testing speed of gas trace leakage detection. The experimental data show that the testing platform can be used to detect three kinds of main cylinder, and can be used to detect smooth,air travel and low pressure sealing performance; the detection efficiency is improved 2~3 times compared with traditional testing methods.