Abstract: In computer graphics, models are often discribed by polygonal meshes. Because the rendering and storage cost is proportional to the number of polygons, too large models are not practical. Model simplification techniques are widely used in computer graphics fields such as computer animation, virtual reality and interactive scientific visualization. In this paper a new algorithm of mesh simplification based on vertex clustering is presented. The algorithm adopts octree structure to subdivide the mesh model adaptively. A new error control method is also presented. The implementation of the algorithm is simple and it runs very fast. Examples illustrate the efficiency of the algorithm.