Abstract: In recent years, with the increasing development of Peer-to-Peer technology, secure issues have become more and more prominent for Peer-to-Peer networks.Peer-to-Peer networks have some new characteristics, such as decentralized, dynamic characteristics, and large scales, which makes the traditional internet security technology unsuitable for Peer-to-Peer networks.At present, Peer-to-Peer networks security researches mainly focus on the trust management and authentication.However, there is little research on access control mechanisms for Peer-to-Peer networks.In this paper, a role-based access control model is combined with Peer-to-Peer trust mechanism, and then an access control model based on trust and role for Peer-to-Peer Networks is proposed.Finally, under the Peer-to-Peer file-sharing environments, the Peer-to-Peer access control prototype system is designed and implemented.The experimental results show that the proposed scheme not only can well adapt to the decentralized and dynamic Peer-to-Peer network environments, but also can efficiently protect the safety of the resources and users.