Wireless sensor network is paid increasing attention and lots of control methods are emerging. However, most evaluation of selforganization performance is still on the stage of qualitative analysis. Focusing on the connection and coverage of WSNs, this paper uses the Delaunay triangulation to describe node entities with their relationships and the information transmission and fusion between nodes. And the Voronoi diagram is applied to evaluate the coverage region of nodes. In addition, this paper uses selforganization degree to make an quantitative analysis on the whole selforganization process. Simulation shows that the proposed method can evaluate the performance of the WSN selforganization algorithms well.