The plane scale ratio of ellipsoidal surface and the gauss are different, which results in the problem of projection distortion. Especially, the projection deformations of the high altitude area and area located at the edge of the Gauss project are larger. Therefore, according to the conventional method, the coordinate system based on the normal method  leads to the reduction of accuracy, which will affect the construction of cities, mines and so on. Using the ellipsoid transformation to establish the regional independent coordinate system can solve this kind of problem. This paper analyzes and summarizes the theory of the ellipsoid transformation to establish the regional coordinate system, and verified by examples. The results indicate that the accuracy of the method of ellipsoid transformation to establish the regional coordinate system is more significantly accurate than that of the traditional method.