Abstract: Trust plays an important role in the interaction of human society, and is focused on in many related research domains. Trust is also introduced to open multi-agent system to help agent choose interaction partner. Reputation can act as one of sources of trust information, which is closely related to trust. Reputation system is a mechanism to evaluate trust in MAS. Research on trust in MAS should take on responsibility of finding the general law of trust among computational entities. The content, rectuirements and applications of trust and reputation system were discussed in the paper.In terms of technology, there arc cognitive and numerical opinions in trust representation, and centralized, distributed and mixed frameworks were adopted by the reputation system. The statistics, probability, belief theory and fuzzy reasioning methods were used to aggregate reputation information. At last, some problems were put forward to study further in the future, which cover group reputation, inaccurate report, lacking of information and interoperation between heterogeneous reputation systems.

Key words: Trust, Reputation system, Trust representation, Framework, Reputation aggregation