Abstract: This paper proposes the method of radial spatial division based on Q i(x i,y i) for realizing the restrained edges mosaic in constructed TIN. First of all, it introduces the basic principle of radial spatial division based on Q i(x i,y i). After that, on the basis of the principle the algorithm to realize restrained edges mosaic is given in detail. A spatial division tree is proposed as an efficient implementation method in the aspect of reconstruction of triangles and their spatial relationship after the division. The analysis of time complexity shows that the time complexity to execute Q i(x i,y i) is lower than that to compute the distance from a point to a line. It is shown that the radial spatial division algorithm proposed in this paper has more advantages in time efficiency than the spatial division algorithm based on distance.