According to the soil parameters provided by the survey report and the structural construction drawings of a one hundred thousand-ton coal wharf in Zhuhai, this paper establishes a three-dimensional finite element model of the coal wharf, including slope model with piles and slope model without piles. The paper firstly analyzes the slope stability of the two models and gives each model’s safety factor, using the theory of strength degradation FEM, and then, further studies the impact of pile foundation on slope stability. The model used in this paper is complex, both geometrically and mechanically, for example, to simulate the real situation as much as possible, the Drucker-Prager and Mohr-Coulomb equivalent area circle yield criterion is used in the slope soil,and the surface-to-surface contact model is used in the pile-soil interface. The paper also figures out the plastic zone and displacement field in both natural slope and pile foundation slope, which may provide references for slope stability analysis of high-piled wharf.