Abstract: Trust assessment, as a key technology in trusted networks, has become a research hotspot of network information security in recent years. The role of trust evaluation in trusted network was expounded. The related concepts and characteristics of trust evaluation of network entities were given, and the trust evaluation methods based on linear weighting, machine learning and Petri nets were mainly introduced. The advantages and disadvantages of the above methods were discussed. Some problems to be solved in the research of network trust evaluation were discussed and future research directions were discussed.