Abstract: In order to analyze the deformation and failure mechanism of the slopes on both sides of the loess gully under the condition of shallow coal seam mining , based on the coal seam mining geological conditions of the Shenyan gully area in the Longan coal mine ,research methods including the three-dimensional numerical simulation calculation and theoretical analysis, are combined to study the stress distribution law of the overlying rock mass,the displacement distribution law , the deformation and failure characteristics and the instability failure process of the slope after coal seam mining .The results show that the displacement of the slopes on both sides of the valley is mainly in the vertical direction, and the horizontal displacement of the slope points to the center of the goaf. The slope can be divided into four deformation zones according to the deformation characteristics: the overburden collapse area within a certain height above the goaf; the loose soil subsidence area in the middle of the goaf; the pull-dump area between the loose soil subsidence area and the surface moving boundary; the unaffected area outside the surface moving boundary.The instability and deformation process of the slope can be divided into four stages: central subsidence - both sides and trailing edge cracking - shear deformation - instability failure.