In order to study the effect of seepage and stress coupling on excavation deformation of foundation pit, finite element numerical analysis method is used in this paper, taking a hanging water curtain foundation pit project under construction in the rich water stratum area of the Yangtze River floodplain as an example. By comparing the deformation index of the surrounding surface settlement foundation pit with different models, the law of the influence of seepage on the deformation of foundation pit excavation is obtained. The results show that when there is no foundation pit dewatering requirement and the support stiffness is large enough, the settlement caused by the release of ground loss stress is small, and the surface settlement curve around the foundation pit is parabolic. When there is precipitation in the pit and considering the support stiffness is large enough, the surrounding surface settlement caused by foundation pit construction is triangular in distribution. The calculation and analysis of foundation pit excavation considering the coupling of seepage and stress in actual excavation construction show that the surrounding surface settlement curve is a combination of the above two settlement characteristics, and the numerical and curve characteristics are coupled.