This study focuses on optimizing the side wall configuration of the inlet pool of the first-level pump station of Fengqing Water Supply Project.A mixture multiphase flow model was developed to simulate the seepage field in the inlet pool.The numerical model's reliability was verified，and subsequent motion analysis was conducted using UGFluent.The results reveal that the diversion flow rate has a more significant influence on flow velocity than the side wall contraction angle.Adjustments to the side wall contraction angle lead to an expansion of the main flow zone and a reduction in the backflow zone，particularly in the area under side wall control.Additionally，high -concentration sediment deposition decreases.The side wall contraction angle also modifies the sediment content evolution in the pool，with increasing angles resulting in lower sediment concentrations and reduced deposition variations across different pool sections.Overall，the optimal hydraulic characteristics and water -sediment features were achieved with a side wall contraction angle of 6°.This research offers a valuable reference for analyzing hydraulic characteristics，water and sediment evolution，and controlling sediment deposition in pumping station inlet pools.