Abstract: There are some advantages as good working conditions，high security，guaranteed production capacity and low loss in open pit mining，therefore the opencast mining is increasing.The numerical simulation and limit equilibrium are used to calculate and analyze the stability of west-side slope 334 in Xiaolongtan Open-pit Mine under conditions of normal and saturation.Slope stability results under the two conditions provide a relative guarantee to take appropriate measures for post-mining safety protection.

Key words: Opencast, Numerical simulation, Limit equilibrium, Stability