Abstract: Pile foundation wharves are commonly used dock structures with widespread applications. The foundations of high-pile wharves, consisting of groups of piles, alter the surrounding hydrodynamic field, causing changes in the sedimentation and erosion patterns, thereby affecting the stability of the dock structures. The study of cylindrical pile group resistance characteristics is of significant importance for the research on water flow and bed-load sediment transport changes. Based on the three-dimensional hydrodynamic model of FVCOM, this study equates pile flow resistance to water flow resistance and proposes a generalized method for the water-blocking effect of pile groups. By adding a pile group resistance term, the study investigates the impact of pile groups on hydrodynamic environmental parameters and constructs a three-dimensional hydrodynamic improvement model for water dynamics below and behind the pile groups. This model was applied to simulate the flow field near a high-pile wharf in Zhoushan, and the results closely matched measured values, proving the model's effectiveness. The findings indicate that the pile group effect results in a decrease in the flow velocity behind the wharf by approximately 67% compared to the front. The constructed model can further investigate the evolution of sediment transportation patterns below and behind the high-pile wharf, providing technical support for wharf construction and operation.