The comprehensive evaluation index system is established and applied in the operation and management of hydropower stations. Based on the cloud model, the evaluation model is established. The weight of the index is calculated by using the combination of the subjective and objective weight methods, known as the AHP and EWM methods. The evaluation grade of the operation and management of hydropower stations is determined by combining the cloud similarity algorithm with the formula for calculating evaluation grade probability. Taking 7 typical hydropower stations as examples, the evaluation grades of the operation and management of the hydropower stations are analyzed, and the comparative cloud maps are plotted. The evaluation grades and the effects of their operation and management visually reflected. The results show that the proposed method has good applicability for the evaluation of the operation and management of hydropower stations.