Abstract: In order to explore the stability change law of the south slope during the process of the inner dumping pressure foot in the south open pit coal mine in Xinjiang, this paper studied the dynamic change law of the slope stability during the process of the inner dumping pressure foot in the south open pit coal mine by means of numerical simulation and theoretical analysis. Firstly, the FLAC3D strength reduction method was used to simulate the process of the inner dumping pressure foot in the south slope, and the variation rule of the potential sliding surface position and stability coefficient in the process of the inner dumping pressure foot in the south slope was obtained. The optimal geometrical parameters of material cross section in the south side of the southern open-pit mine are obtained. Based on the numerical simulation results, the limit equilibrium theoretical model of the inner dumping pressure foot in the south slope was established, and the calculation formula of the stability coefficient of the middle south wall in the process of the inner dumping pressure foot was deduced. The evolution law of slope stress in the process of pressing foot in the south slope is expounded and the mechanism of the change of the position of the potential slip surface and the improvement of the stability of the middle south wall in the process of the inner dumping pressure foot was expounded.