Against the backdrop of rapid urbanization and high-density urban expansion, the construction environment of urban rail transit is complex, and the adverse social impacts and safety accidents caused by settlement of surrounding houses and road surfaces due to foundation pit construction are not uncommon. As one of the important risk sources in the construction process of deep foundation pits, depressurization and precipitation of pressurized water are crucial. It is particularly important to control them reasonably and minimize the adverse effects of precipitation on surrounding buildings (structures) while ensuring the safety of the foundation pit. This article takes the deep foundation pit project of a station on Shanghai Metro Line 21 as an example to introduce the overall idea of fine control of deep foundation pit depressurization and dewatering. Combining on-site pumping tests, numerical simulation calculations, excavation condition subdivision of foundation pits, and digital dewatering systems, the adverse effects of depressurization and dewatering during excavation on the outside of the pit are greatly reduced, maintaining the safety of surrounding buildings and providing reference and inspiration for the construction of similar projects in the future.