The high slope of the hydropower project is a complex system jointly affected by many internal and external factors. There are different kinds of methods used for overall stability evaluation of high slopes, but these traditional methods usually have some shortcomings. A high slope stability evaluation method is proposed in view of the difficulties in determining the weights of the index and the fuzzy membership degree. Constructing a multi-factor coordination index system and grading the standards for the high slope stability evaluation, comprehensively utilizing the combined subjective and objective weighting methods of the ladder level index, and considering the fuzzy and stochastic characteristics of the evaluation indices, a cloud model suitable for high slope stability multidimensional cascade evaluation is established with the aid of the fuzzy entropy and cloud theory. The left bank of the Jinping hydropower station (the first cascade) is taken as a case history to study and analyse in order to demonstrate the validity of the proposed method mentioned above, comparing with the calculated results given by various evaluation methods.