Based on a thorough study of the topography, rock structure, and engineering geological characteristics of the toppling rock mass on the right bank of the Miaowei Hydropower Station, a three-dimensional block discrete element method 3DEC was used to establish a numerical model of the toppling deformation body on the upstream side of the right bank dam foundation. The stability of the toppling body under different working conditions of the natural toppling body and construction period toppling body was numerically simulated and studied, and the characteristics of the toppling body damage deformation and plastic zone distribution during each process were obtained, revealing the potential instability and failure mechanism of the toppling body; Based on field monitoring data, conduct quantitative analysis to study the time-dependent deformation characteristics of the toppling body. The research results show that the overall stability of the natural toppling body on the right bank is relatively high, and the safety factor can reach 1.39. The potential instability area is related to the excavation unloading process and exhibits a gradual damage evolution characteristic of the toppling rock mass. The slope system anchor cable has a significant controlling effect on the deformation of the toppling rock mass, greatly limiting the deformation of shallow A and B₁ toppling rock masses on the slope surface. The monitoring data shows that the deformation of the toppling body on the upstream side of the right bank dam foundation lasts for a long time after excavation at the foot of the slope, and is severely affected by rainfall, resulting in a significant time-dependent deformation process.