Due to the technical and standard advantages of GPS in the world, most of the satellite based navigation systems used in the field of civil aviation are GPS. With the rapid development of civil aviation in China and completion of BDS-3 constellation deployment, it is necessary to evaluate the application performance of the BDS ground based augmentation system in the civil aviation field, to verify whether it can meet the requirements of civil aviation aircraft for satellite navigation system. According to CAT-I operations of civil aircrafts, this paper has investigated the performance requirements of ICAO for the satellite navigation system during precision approach, derived the mathematical model of the vertical protection level of the BDS GBAS, formulated the modification scheme and flight subjects for carrying test flight, performed BDS GBAS flight test, and analyzed the positioning accuracy and vertical protection level of BDS GBAS. The results show that the BDS GBAS in this flight test can meet the vertical precision requirements of CAT-I operations to the satellite navigation system, and there is no alarm and false alarm in the system.