Abstract: A mega landslide incidence occurred in Pusa Village, Zhangjiawan Town, Nayong County of Guizhou Province was taken as an example.After geological investigation, we found the main sliding direction of the landslide was 310°,with a length of 720 m, a width of 360～380 m, and an overall volume of about 82.3×10⁴ m³,which was recognized as a medium-sized landslide.The stratigraphic lithology of the slope body consists of the upper permian longtan formation, changxing-dalong formation, and the lower triassic yelang formation, showing the evolution of paleoclimate changes and depositional environment.Slope stability is affected by a variety of factors, including dominant factors such as microgeomorphology, lithologic assemblage, slope structure and weathering, as well as triggering factors such as goaf, strong rainfall and vibration of mining and blasting.In order to study the slope failure and slide, a numerical model was constructed using a two-dimensional discrete element numerical method, which considered the interaction of multi-layer coal mining seams and simulated the deformation and failure characteristics under different loads.The study shows that coal seam mining, heavy rainfall and blasting vibration have a significant effect on slope stability.