The project has realized the design of portable BS(Base Station) Test System(BSTS) with GSM900/DCS1800 dual-frequency for the base station sensitivity testing to mobile communication system operation maintenance. The BSTS is composed of the GSM card, signal processing and control unit and notebook computer. The static sensitivity test accuracy of the GSM base station receiver is ≤±3 dB, test distance is ≤1 000 m (Line Of Sight，LOS), test time is ≤10 s. It supports two or more GSM modules or a single GSM module with self-loop back sensitivity test.