Abstract: Dam break will cause catastrophic loss of life and economic damage.Therefore, it is essential to evaluate the risk of the dams accurately and prevent it in time for the safe operation.Based on Dagangshan high arch dam, the cloud model was used to evaluate single-factor risk level and the entropy weight method was used to comprehensively evaluate dam safety level according to the complexity and randomness of dam stability influencing factors.Firstly, we analyzed the risk factors affecting the dam's stability in detail, determined the evaluation index system of the factors affecting the dam's stability, and obtained the influence scores of each factor using expert scoring.On this basis, the cloud model was used to divide the risk level of 25 three-level risk indicators, and the results show that the risk indicators were located in the middle and high-risk level intervals.Finally, the entropy weight method was used to determine the total weight of each three-level index.The stability-weighted score of the Dagangshan high arch dam was 5.69 points, corresponding to the safety level of III.The evaluation results of the cloud model-entropy weight method are reliable and in line with engineering practice, which can provide a reference for dam risk evaluation.