Abstract: Generation of triangular meshes for digital terrain model is studied,the triangulation algorithm of discrete points and edges and its data structure are presented.Occurring in digital terrain model constructed from contours,the flat region fails to reflect the true shape of the surface,so a corrective method of flat triangles is also provided.According to this approach,a computer program for constructing digital terrain model from contours is developed using Microsoft Visual C++4.2on the AutoCAD R14for Windows platform.