In order to solve the problems of groundwater leakage of row-pile retaining structure and foundation pit deformation in water-rich sand stratum, based on the deep foundation pit engineering of metro station, the variation law of lateral displacement of retaining wall, ground settlement and internal force of retaining pile under curtain partial leakage in sand soil site are studied and compared by means of numerical simulation and field measurement. The results show that the curtain partial leakage exacerbated the effect of seepage action on the deformation of foundation pit, the lateral displacement curve of retaining pile develops from a oblique line shape to a parabolic shape with an increase of excavation depth, and the lateral displacement curve of deep soil develops from nonlinear parabolic shape to linear distribution with an increase of lateral distance Lp. The curtain partial leakage leads to the ground settlement and influence area increasing, and the significant influence area of ground settlement after groundwater leakage expands to (2.0~3.0) times of that before groundwater leakage. The internal force of retaining pile increases with the excavation depth's increasing, and the maximum shear force and bending moment of retaining pile after groundwater leakage are lower than that of before groundwater leakage. It is an effective way such as blocked leakage passage and reduced soil erosion to control leakage disaster deterioration of foundation pit. The research results can provide reference for the hazard prevention and construction control during the groundwater leakage of deep foundation pit in sandy soil site.