Abstract: This is one of results of 3-D reconstruction of urban buildings and visualization of city models. On the basis of common 2-D triangulated irregular network (TIN). This paper developed 2D-TIN under determined boundary condition, through respective generation of 2D-TIN of irregular roof and vertical wall concerning the terrain, composed 2-D TIN of building surface, realized 3-D visualization method of urban buildings concerning the terrain after expunction of common side under same plane condition, inborn data in DXF format can access directly AutoCAD、 3D Studio and OpenGL.