A remedy scheme of water leakage in the deep foundation pit of a subway station is introduced. The deformation and axial forces of the supporting structure as well as the underground water level were monitored during the leaking prevention process. At the same time, a plane model was developed to simulate the construction process of foundation pit by FEM. Then, the fundamental reason for the leaking of the foundation pit was analyzed by numerical results and in situ measured data. Furthermore, importance of the strength of the supporting structure to the excavation of the foundation pit was also detailed demonstrated. Finally, the remedy measures were put forward to prevent the water leakage, which were proved to be effective and feasible in practice.