This article presented a subject trust model based on fuzzy comprehensive evaluation, and gave the concrete method of realizing the model to evaluate the trust degree of a subject in the network. The article could confirm the weights of evaluation factors dynamically by means of Analytical Hierarchy Process(AHP), and drew into the weights that expert had made for evaluation functions, to make a twice comprehensively evaluation for the first consequence. Example analysis showed the correct, novel and practical value of the method.