A novel dynamic trust model for network service is proposed. The corresponding relationship of trust evaluation and interval-valued intuitionistic fuzzy numbers are introduced in the computations，compounds，and general operations of experience of trust，neighbor recommendation trust and agency recommendation trust，which are based on trust demand attributes. Meanwhile，the trust attributes’ weight factors are determined by precise function proportion，while time series weight factors are defined by the inverse form of exponential distribution. And the trust service is finally distinguished by the result of general trust scoring function and psychological factors. Simulation results show that the model can effectively build trust relationship between entities and restrain attacks from malicious entities.