Abstract:Be aimed at the characteristics of subjectivity and uncertainty of trust in the Web service, a trust modeling method based on the cloud theory was proposed. The calculation methods of direct trust cloud, recommendation trust cloud, comprehensive trust cloud and the update algorithm of trust based on the weight of time was also presented. Meanwhile, this model use the information of the service capacity that resources could achieve to quantify the trust of service, which enhances the objectivity of model. It can evaluate the real level of trust and increase the interaction success rate of entity. The experiment and analysis results show that the cloud-based trust model proposed performs well in network.