Abstract: At the boundary of the Bijigou open pit,the final height of the slope is 510 m,half of the slope and half of the depressed surface.Side slopes at line 8~15 is complex in shape.In order to determine the reasonable final slope angle,the slope stability of several typical sections was studied by FLAC3D,and the slope angle and the step structure parameters were determined respectively.And the local reinforcement parameters for each part are put forward.This method is suitable for studying the stability of rock slope,and determining the final slope angle in feasible,economical and reasonable ways.

Key words: Open-pit mining, Slope stability, The final sloping angle, Fast Lagrange finite difference method (FLAC3D) , Anchor cable reinforcement