Abstract: Four typical slope sections were selected and six optimal slope angle designs were provided according to the geological conditions and the slope morphology formed by the mining operation in an open pit mine.Morgenstern-Price method was used to calculate the slope safety factor，and all slope safety factors are greater than 1.0.But the limit equilibrium method does not consider the spatial variability of rock and soil parameters，which can not reflect the slope safety comprehensively.In light of the advantages of reliability analysis method，Monte Carlo simulation method was used to carry out the stochastic simulation experiments.The analysis results showed that the slope designs′ average safety factor provided by the reliability analysis method were closed to that by the limit equilibrium method，but the failure probability are within the acceptable failure probability threshold，and the reliability index is greater than the minimum acceptable reliability index.All the slope designs meet the engineering stability requirements.

Key words: Slope, Reliability, Monte Carlo simulation method, Design optimization