Abstract: In order to improve the recovery rate of open-pit coal mine resources, under the condition of studying the deformation and failure mechanism of the slope, the horizontal mining is carried out and the stope shape is optimized. Taking the Thar coalfield in Pakistan as the research object, the paper firstly analyzes the deformation and failure mechanism of the slope through FLAC^3D, clarifies the landslide mode, and then analyzes the tracking distance of the horizontal mining and inner row, and finally provides a reference for the optimization of the coal mine. The results show that the failure type of the slope belongs to the tension-shear composite type, and the stability of the slope increases as a whole due to the double support effect of the slope working aid and the inner dump. When the tracking distance of the inner row is 50 m to 100 m, the three-dimensional spatial effect of the slope is significant, and the stability is high; as the tracking distance increases, the stability becomes worse and worse.