Combining with the deep foundation pit slope project of the second ship lock of a hub，we establish a generalized model，analyze the stability of the weak interlayer slope by the strength reduction method，and compare with the code to obtain that the slope should be reinforced. We study the influence of the pile position on the stability of the slope when carrying out anti-sliding support for the interlayer slope，and analyze the internal force distribution law of the anti-sliding pile under different pile positions. The results show that when the anti-sliding piles are arranged from the bottom of the slope along the slope face to the top of the slope，the safety factor of the slope first increases and then decreases，and the plastic strain of the plastic zone first decreases and then increases. The critical point of the direction of the anti-sliding pile’s shear force reversal and the maximum value of the bending moment were both located near the weak interlayer. When the anti-sliding pile is located in the middle of the slope，the slope safety factor is the maximum，the plastic zone is the smallest，the shear force and the bending moment of the anti-sliding pile are the largest，and the anti-sliding effect is the best.