Abstract: With the development of the entities and concepts such as urban underground complex,rail transit and sponge city,the building space extends deeper to the underground,groundwater control becomes more and more prominent in the construction,and its influence on environment and groundwater safety is more and more important,especially for the multilayer groundwater research and control scheme.It is the development direction of the deep foundation pit design that curtain of water cut is selected with a small amount of dewatering method.Based on the analysis of the actual cases,the upper ground water is obstructed by the curtain to the bottom,the suspended curtain is used to control the underground water,and the empirical coefficients of the water outflow is studied and counted in the foundation pit of the suspended curtain.