Abstract: With the construction and development of BeiDou satellite navigation system, we are committed to providing stable, reliable and high quality satellite navigation services to global users and promoting the development of global satellite navigation in civil aviation. This paper introduces the positioning error of the satellite navigation system and the main factors that affect the positioning accuracy. By comparing with the GPS／INS navigation data as the true value data, the positioning accuracy of the dynamic test points in different altitude regions is analyzed. Firstly, the distribution of DOP and the number of visible stars in the measured data is simulated and analyzed for the high altitude mountain range and the low altitude plain area, and the dynamic positioning accuracy of the two kinds of altitude is statistically analyzed. The results of the measured data show that the Beidou satellite navigation system can provide real-time navigation and positioning services both in the low altitude plain and in the high altitude mountain range, and can calculate the dynamic positioning accuracy of the satellite system, and the positioning results are in compliance with the standards of "BeiDou satellite navigation system performance standards for public service", to meet the user's positioning requirements.