Abstract: Slope stability has always been the key research object of slope safety. In view of the common uncertain factors in slope evaluation, reliability analysis is a valuable method. To evaluate the stability of a jointed rock slope, a point estimation (PEM) calculation probability model is established by using the finite element analysis software and the field survey data, The PEM method takes the joint strength parameters c, φ and the safety factor as input and output variables. The results suggest that, the joints have a significant control effect on the deformation of the slope; The overall reliability of slope is great, and the failure probability is extremely low. Finally, the reliability results are verified by Monte Carlo method, and the results show that there is no significant difference between the two methods. The results indicate that the joints have good sensitivity to the stability of rock slope, and the point estimation method based on joint uncertainty is an effective method to analyze the slope reliability.