As a new type precise approach and landing system based on satellite navigation system, Ground Based Augmentation System (GBAS) is greatly different with traditional ground-based radio precise approach and landing system on system architecture and application, therefore, flight inspection for GBAS system is also different with ground-based radio system on contents and methods for flight inspection. This paper presents the performance analysis of GBAS ground subsystem according to the flight tests results on several china airports, those flight tests were carried out by ChinaFlightInspection of CAAC. The analysis showed that GBAS system can satisfy the accuracy requirements for CAT I approach and landing navigation system, VDB signal coverage and data continuity also satisfy the test requirements.