Abstract: With the development of network technologies, such as P2P and grid, system environment becomes more open and the relationship of the entities is not so intense. Hence, trust model becomes focus of intense research. Trust model establishes a management framework of trust relationship between entities, but its open nature makes it easy to attack by every malicious evaluation. To minimize the influence of the malicious evaluation to the trust model, a novel trust model based on trust area and evaluation credibility is proposed, which is suit for the open distributed network environment. At the same time, the flow sheet of the model and the relevant definitions are given in the paper. The model is built based on the trust area, and the reputation value of a node is composed of the service credibility and feedback credibility. The distinguishing algorithm of the colluding clique is presented based on the similarity of peer’s evaluation. A new method on how to determine the feedback weight is proposed, which depends on the evaluation support and evaluation consistent factor. Simulation and analysis show that the proposed model can distinguish and resist the malicious evaluation effectively.