Abstract: Visualization is an indispensable part in scientific computation. The main task of visualization is to convert large amount of complex data produced by numerical simulation into graphics and/or images by means of computer technology. Meshless method is a numerical simulation method based on discrete points. Since there is no connecting information between each point, it is difficult to realize visualization in the post process of its numerical results, especially in the case of random distribution of discrete points. Delaunay triangulation is a useful tool for the visualization for random distributed points. Unique approximate-equilateral triangles can be obtained from a set of random distributed points by Delaunay triangulation. The basic principles of Voronoi cells and Delaunay triangulation are introduced in this paper. An algorithm of Delaunay triangulation and a way to realize the visualization of numerical results for meshless methods are developed. Several application examples of visualization for meshless method are presented.