Abstract: In this paper, we present a new time-space based trust model which integrates time and space factors, where short-term-trust, long-term-trust, abuse-trust and feedback-trust are the main consideration. Furthermore, the community-trust is proposed to solve the difficulty of binding between user and physical IP address. The community-trust indicates the integrative trust level of users' physical locations set in a specific range. Theoretical analysis and simulation results show that the time-space based trust model is effective on modeling dynamic trust relationship, aggregating feedback information, and resisting some attacks such as slander, peer collusion, and Sybil attacks.