In recent years, GPS space geodetic control network technology has been widely used in more and more areas, but rarely in hydrology departments. This paper discussed the basic principle and workflow of using a satellite navigation system for leveling ，and the differences between the GPS space geodetic control network technology and the ordinary leveling. In this study, we found both their own advantages, disadvantages and highly complementary. With the technology advancement and economic development, especially the China's own Beidou satellite navigation system, application of the satellite navigation system in geodesy will enter into more areas including the hydrological departments.