Abstract: In order to study the deformation and failure process of rock slope induced by repeated mining under high and steep mountain body, a numerical calculation model of coal seam mining under high and steep terrain was established by using the method of discrete element numerical simulation. The progressive failure process of rock slope deformation induced by repeated mining was analyzed from horizontal and longitudinal displacement nephograms. It is concluded that there are three stages of slope collapse induced by repeated mining under high and steep mountains, namely, initial deformation stage of coal seam, uneven subsidence and cracking stage of slope caused by repeated mining, and instability and failure stage of slope. At the same time, it is concluded that the uneven deformation of the slope results in different forms of damage at different positions of the whole slope. The final instability forms of the slope surface are landslide and collapse, which are mainly determined by the original topographic gradient and stratigraphic lithology of the slope.