iThe Constrained Delaunay Triangulation is one of the most typical algorithm in computer graphics. But it still has some limitation. Thus we want to do some changes to make it more efficient. Our main work can be divided into two parts. Firstly, we design a algorithm to improve its readability and execution efficiency. In this part, we adapt the thought of polygon’s successive division and create a polygon class, for this mainly using C++ and OpenGL languages to realize. Secondly, we design another algorithm to expand its application scope. Main thought is the cross determination for selecting the eligible diagonals. Experiment showed we have achieved expectation effect to some extent.