Abstract: The dynamic mechanism of credit system construction is studied. Firstly, from the perspective of system dynamics, a dynamic model of credit system construction is established and the initial state and equation designed based on the actual system. And then, the model is simulated, and the simulation results show that the more integrity the credit system has and the more transparent the credit information is, the less the supervision strength is, which can effectively reduce the regulatory costs and promote the social credit level. With the credit of business more sensitive to the change of credit system, personal credit is more sensitive to information change in the long term while the government plays a vital role in credit system construction. At last, based on legislation and information services, policy proposals for credit system construction are put forward.