Abstract: With Yinshan mine as engineering background,and based on the field investigation of regional geology and the slope sliding type,the sliding mode of high steep slope in Yinshan Mine and the factors for destabilization were analyzed according to the theory of mechanics for slope sliding.Based on this,the integrated stability of each slope were contrasted and analyzed by strength reduction method and FLAC3D numerical method,meanwhile considering the water permeation.The results showed that:the optimal slope angle at section 1,section 2 and section 8 of North-East slope can reach 44°,46°and 45° respectively after optimization.The optimal slope angle at section 3 and section 4 of North-West slope reach 45°and 48°.The optimal slope angle at section5 and section 6 of Western slope is 46°and 44°,and the optimal slope angle at section 7 of southern slope is 44°.The mine design with slope angle of 45° is wholly optimized,which has practical significance on keeping slope stability.Meanwhile,the research provides guidance to safety production of Yinshan mine. High slope|Strength reduction|Slope angle|Optimization