Groundwater seepage poses a threat to the foundation pit safety.Based on the example of deep foundation pit engineering,the three-dimensional seepage model is established.According to the seepage numerical simulation of a foundation pit at excavation stage in Handan city,the pore water pressure distribution rule in soil of foundation pit in time and space at excavation stages were analyzed.The result showed that the groundwater flow into the internal foundation pit from the external in the process of excavation,and active pressure and passive pressure zone were formed.The conclusion provides theoretical guidance for the design and support of deep foundation pit.