The risk assessment of social stability of key water conservancy projects is studied from the aspects of evaluation subject, evaluation content, index system, evaluation methods and evaluation process. Owing to that the existing researches define the social stability risk from its causes and the definition, in the future, all the evaluation contents should be more comprehensively taken into account, and it should combine the external environment with the project itself. The public participation index is added into the evaluation index system. For selecting the evaluation method, the analytic hierarchy process and the fuzzy evaluation method are combined to learn from each other. The results are of great significance to improving the assessment of social stability risk.