Abstract: The rock mass quality classification in slopes is a complicated geology problem.It includes many factors including hydrological geology, engineering geology,rock mechanics,and excavation condition.This paper uses the fuzzy analytic hierarchy process(AHP) method for rock mass quality classification in slopes.It uses the AHP method to divided the hierarchy structure of the relevant factors,and uses the fuzzy method to compute the weight of each factor.The evaluation standards for each factor and for slope rock mass quality classification are established simultaneously.At last,the proposed method is illustrated with an example and compared with other methods.The usefulness of the proposed is verified.The proposed method can be considered as an extension of the existing method of rock mass quality classification.