Abstract: This paper aims at the problem of slope deformation and instability induced by the water from the burnt rock aquifer seeping into the basement of the dump. Taking the slope of an open pit mine in Xinjiang as the background, the water seepage law of burnt rock aquifer in the slope and the deformation and movement law of rock and soil mass in the slope are studied by numerical simulation method, based on the method of ultimate bearing capacity estimation under the condition of very thin topsoil and thin topsoil basement, the ultimate height of the inner dump was determined, the limit equilibrium analysis method is used to optimize the soil discharge parameters of the inner dump. Through the research, the discharge parameters of the soil dump in the weak basement under the influence of groundwater infiltration are determined.