Abstract: Based on the actual deformation data of suspended curtain deep foundation pit of metro lines in flood plain areas, the deformation laws of the deep foundation pit are analyzed to provide a reference to the design and monitoring of similar projects by using the methods of theoretical analysis, empirical formulas and finite element numerical simulation. The results show that the distribution curve of the ground subsidence behind the suspended curtain takes a shape of groove. The ground subsidence considering fluid-structure interaction is greater than that without considering fluid-structure interaction. The final shape of the underground diaphragm wall is convex. The horizontal displacement of the wall at the top does not completely move to the pit. The ratio of the maximum horizontal displacement of the diaphragm wall to the excavation depth of the foundation pit is similar to the situation of the foundation pit with wholly used waterproof curtain. The depth of the maximum horizontal displacement point is near the bottom of the foundation pit. The ratio of the ground subsidence caused by precipitation to the total subsidence is about 0.54. The range of ground subsidence can be divided into strong, moderate and weak influence areas. The curve of ground subsidence in each influence area can thus use different functional expressions. The location of the maximum ground subsidence point is farther than that of the foundation pit with wholly used waterproof curtain about 1.0~3.0 m under the same conditions.