Abstract: This study investigates the impact of seepage on the surrounding environment during foundation pit excavation and explores effective numerical simulation methods to address this issue. Based on the Dongtai Comprehensive Hub deep foundation pit project, an excavation and seepage coupling model was established using ABAQUS finite element software. The model simulated soil deformation and pore water pressure changes during excavation. By comparing pre-and post-excavation models, the specific effects of seepage on surface settlement and soil deformation around the pit were analyzed. The results show that seepage significantly increases soil deformation and surface settlement, especially in areas with greater excavation depths. This effect can adversely affect the stability of nearby structures. A 35 m deep cutoff wall effectively reduced pore water pressure changes outside the pit, enhancing the stability of the surrounding area. Groundwater seepage significantly increased soil deformation both inside and outside the pit, particularly bottom heave. Therefore, monitoring and controlling groundwater seepage during design and construction is essential to mitigate these adverse effects. This study combines a practical engineering case with numerical simulation to comprehensively investigate the impact of seepage during foundation pit excavation. It provides actionable recommendations to reduce seepage effects, such as optimizing the excavation sequence, adjusting support structure design, and enhancing groundwater seepage monitoring and control. These measures offer valuable references for similar projects, contributing to the safety and stability of deep foundation pit engineering.