Abstract: As an existing method, Quasi_Stable Adjustment which is often used to align local CORS position to CGCS2000 at present, has some limitation. This paper focuses on studying the methods of calculating the real position of GPS stations at the reference epoch of CGCS2000 from GPS observations obtained from various observing times, two methods are introduced here. One is to align the position of GNSS stations to CGCS2000 through adjustment with coordinates of CGCS2000 reference stations constrained tightly, while the other method is to transform the coordinates of the GNSS stations to CGCS2000 through their velocities. In order to demonstrate the difference between these two methods, nearly 1800 CORS's observations about one month collected from 30 provinces in China were processed and transformed with the two methods. The conclusion derived from the results analysis shows that the maximum transformed difference between Quasi_Stable Adjustment and CGCS2000 will be dm.