The GBAS system will improve the navigation accuracy by using differential positioning. With the help of integrity monitoring algorithm, the system will keep a high accuracy, continuity, integrity and availability index. The airport covered by the GBAS system is to obtain a I class precision approach (CAT-I) even higher precision approach and landing guidance services. The purpose of the flight test for GBAS is to confirm the signal stability and reliability of the GBAS ground equipment. The cross-linking ability of GBAS ground equipment and aircraft airborne equipment will be verified at the same time. The paper mainly introduces the system composition and working principle of the GBAS system, and focuses on the flight test method as well as the conclusion of the data analyzing in Tianjin Binhai International Airport, which provides a way of evaluating the GBAS performance as well as a technical basis of popularization and application