Abstract: This paper presents a novel decentralized trust management model with reputation. In P2P (peer to peer) network, there is no trusted authority. Trust relations between peers should be established with peers behaviors. There are three main contributions in this paper. Towards utilizing time self-decay function, the time-related problem is resolved. Also through comparing the nearly scores and general scores, the problem of servents subjective expect can be resolved. After using the DHTs, bandwidth cost can be reduced and salability can be obtained. This model can promote the business succeed rate in P2P network efficiently.