Abstract: With the increase of exploitation depthin the openmetalpits,the slopesheightareincreased continually.The in-situ stress in the mining areaand the pore water pressure in the slope are shown as disturbed and complicated.Also,they are the non-ignorable factors for the slope stability.So it is an urgent and complex problem to simulate the real slope stabilityaccurately.In this paper,based on the in-situ stress monitoring data,hydrologic condition surveying data,practical engineering geological structure,a 3D model was built in the FEM software FLAC^3D,to accept the constitutive parameters,the in-situ stress boundary conditions and fluid-solid coupledconstitutive relation.After combining the pore water pressure contours,the contrastive analysis on the displacement and the plastic damage zone contours,the whole displacement is vertical sedimentation,and its value is much smaller.The main damage occurred on the surface of slope.The whole slope stability is better,but,some partial collapses appeared at toe,surface and top of slope.