Community finding of virtual user network on the Internet has provoked more and more researchers? interests in the field of computer and physics field recently. Existed results focus on how to seek a reasonable and feasible algorithm to find the communities of virtual user network mostly, but scarcely relate to the centrality of those found communities. In addition, the centrality of those found communities is usually not involved. In this paper, the topology of virtual user network is analyzed firstly, and it shows that the network has a scale-free characteristic. The straightforward and effective criterion evaluating the correctness to detect the community structure has been established. Then the mining system for community finding and centrality of the network is designed and its workflow is presented. Two key modules of this system, community finding module and centrality module, are studied in detail. An implementation example is given to verify the validity of the design. Finally, the paper is summarized.