A group-oriented access control scheme is proposed for P2P (peer to peer) networks. In the proposed scheme, authentication control, admission control and revocation control are used in order to provide security services for P2P networks. Moreover, the proposed scheme can simply and efficient establish share key between two members without interactions, therefore it can perform secure communications with them. The analysis of security and performance shows that the proposed scheme not only can realize authentication and secure communication, but also can easily and efficiently add new group members and revoke malicious group members. Therefore, it is more efficient, and more practical protocol for P2P networks.