Ground stations of GBAS carry out carrier smoothing pseudo distance and the integrity monitoring, generate pseudo-range correction information and broadcast differential GBAS TYPE message and then airborne users receive GBAS signal for pseudo-range differential positioning, and complete approach guidance. This paper mainly introduces the system composition, working principle, GBAS testing and data analysis, etc. of the GBAS system, which provides a technical basis for the test verification and performance evaluation of domestic GBAS ground equipment and the qualification verification and testing.