Abstract:The stability of jointed rock slope is controlled by the shear strength of joints and rock block simultaneously. Based on the research of failure mode of jointed rock slope with two sets of joints,the fuzzy characteristics of mechanical parameters in jointed rock slope are taken into account during stability analysis by fuzzy method. Formulae are proposed for the calculation of fuzzy safety factors of jointed rock slope. A program that can automatically search the potential sliding surface of jointed rock slope is also presented. The case study results indicate that the fuzzy analytic approach for stability analysis of jointed rock slope can offer more objective knowledge for slope stability and reference to bolt design when the jointed rock slope is unstable;therefore the failure situation because of the uncertainty of parameters can be avoided effectively.