Abstract: There are many faults in the north of Dumu mining area of Gongchangling Open-pit mine.In order to determine the influence range of fault and the influence of slope stability and slip mode，6 kinds of working conditions are divided to research according to the difference of fault location：In initial position，fault is moved to the inside of the slope of 30 m，60 m，90 m，120 m and there is no fault.FLAC and Geo-Slope software are used to simulate the 6 kinds of working conditions.By comparing the maximum shear strain，horizontal displacement，vertical slice and slope safety factor，the influence of fault location on the stability of the slope are analyzed.Results show：When the fault is less than 100 m to the slope，the slip mode of the slope is the plane-shear arc sliding mode with the fault as the lateral boundary，and the slope stability is poor；When the fault is more than 130 m to the slope，the slip mode of the slope is no longer affected by faults，the potential slip surface is single shear arc，and the slope stability is better.The research results has a great reference value to the mining plan and the slope design of the mine.

Key words: Slope stability, Fault, Slip surface, Numerical simulation