Infinite rock slope stability analysis is highly amenable to probabilistic treatment. To assecess the probability distribution of the safety factor of the infinite rock slope using the jointly distributed random variables method based on the equivalent parameters derived from the Hoek-Brown criterion, the program on the basis of the MATLAB is provided, and the results verifies the feasibility of this method and shows the safety factor approximately obeys the normal distribution. The sensitivity analysis to the 4 parameters shows that the most effective parameters are ci and r.??