Abstract: There are many risk factors in the implementation of projects in the Belt and Road initiative, and the project risk transmission is the basis and key to improving the cooperation efficiency of the Belt and Road projects. This paper analyzes the risks in the hydropower project construction and establishes a feedback loop diagram of risk transmission. Based on the system dynamics and structure entropy weight method, a quantitative system dynamics model is developed. We establish a risk transmission model for the Belt and Road hydropower projects, assign values to model variables, and determine variable weights and functional relationships. Combined with the case study of CC/LB Hydropower Station in Argentina, the impact of different risk management levels and contract renegotiation on project risk is simulated, and the characteristics and impacts of project risk transmission at different stages are analyzed. Based on the results, risk control measures are proposed. This model enables the practitioners to cope with the uncertainty and dynamics of project risks, reduce risk levels and improve project investment efficiency.