Abstract: Most of the existing peer-to-peer (P2P) systems assume that the peers in such a system form groups, yet little research has been done discussing how such groups form and remain stable as nodes interests change. Referring to the human society organization, a method of self-organizing P2P network based on community is proposed. According to the peer's resources and query requirements, the P2P network is organized by resource community and demand-oriented community. As resources and demands change, peers dynamically adjust their configuration and move to the right community gradually. The simulation result indicates that the proposed method can automatically optimize the network so that each peer can maintain near neighborship with peers with similar resources or provided resources. Also, the experiment proves that the employment of self-organization mechanism leads to adaptation as well as scalable P2P network construction technique.