Abstract: With the south slope(footwall) of an open pit in Zambia as a research subject,the Rosenbluth point estimation method(PEM) coupled with the jointed finite element method(JFEM) was applied to this jointed rock slope stability evaluation. A probability model was established,which puts the mean and standard deviation of rock material strength parameters(friction angle and cohesive) as input variables and the safety factors as output variables,and the point estimation state functions were solved by the jointed finite element method. According to on-site joints and structural surface surveys,a jointed slope model was built to solve the safety factors,and then the probability distribution of the safety factors was obtained. The results of probability analysis are consistent with the instability situation on site. Since the uncertainty of rock materials and the properties of rock joints are taken into account,this method fully reflects the role of the non-linear relationship among rock layers and makes the rock slope stability estimation more reasonable.