Abstract: The current EigenRep trust model could not make reputation punishment correction to the cheating behavior of malicious peers．To solve this problem,this paper improved the global reputation computing method．Many comprehensive factors in computing trust value are introduced in the mechanism．Moreover,another defect of EigenRep is that the system has to do the iterative calculation of global credibility within the whole network for each transaction,and this causes the system cost problem．To solve this problem,this paper presented a new trust mechanism which combines risk,local trustworthiness and global reputation．Simulations show that this mechanism could reduce the system cost greatly．At last,this paper realized an E-commerce platform system based on this trust mechanism.

Key words: Trust network,EigenRep,E-commerce,Trust mechanism