Abstract: Water and soil changes caused by deep foundation pit excavation engineering and dewatering lack research. Taking the deep foundation pit project of Wangzhuang Road Station of Wuxi Metro as an example, the variation law of dewatering over time and space is analyzed by detecting foundation pit underground water level, pore water pressure and flow volume of dewatering well on site. By detecting soil settlement and horizontal displacement of enclosure structure, the deformation and seepage characteristics caused by foundation pit dewatering are studied. Research results show that during the process of foundation pit dewatering, the reduction of deep stratum pore water pressure is larger than that of shallow stratum pore water pressure. The water flow volume of single well of confined well is obviously larger than that of drainage well at the beginning, then the water flow volume of confined well is gradually stable. The drainage well water flow volume gradually decreases as time passes. In the process of foundation pit dewatering, the soil settlement close to the pit is larger at the beginning, and the soil settlement far away from the pit increases gradually over time. In the process of foundation pit dewatering excavation, the horizontal displacement of foundation pit shows trend of increasing first then decreasing along the buried depth of soil. The maximum displacement occurs in the middle of diaphragm wall.