Abstract: As there is no central authority in a distributed network, Thus an agent lacks sufficient global knowledge, and it is difficult to evaluate the degree of trust on an agent. After consideration on synthetic reputation value in the nature of globalization and objectivity and trust value in the nature of localization and subjectivity, in dealing with problems a new trust evaluation model called the four rule model is proposed. This model contains the reputation computing rule, trust recommendation rule, reputation weight rule and trust computing rule. And the paper compares this model with the attack-resistant trust metrics model in the aspect of security. Theoretical analysis and simulation experiment showed that the proposed model is more robust on trust security problems.