Abstract: The open and anonymous nature of a P2P network makes an ideal medium for many applications.The peers are not willing to be responsible for their historical behavior because of lack of supervisor;and it's not easy to set up a trust mechanism in a traditional way to solve the problem during the transaction.In this paper,we proposed a recommendation-based trust model,and introduce some feathers to implement the trust in P2P networks.A peer's trust value is calculated according to the interacting experience and recommendation obtained from other peers.Compared with some existing models,our approach can stimulate the feedback and decrease the dishonest behaviors efficiently.The computer simulation results show that the trust model can prevent the attack of malicious peers' recommendation.Meanwhile,it solves new peer's trust problem and strengthen network security.