Abstract: In order to reduce excessive exploitation of groundwater resources and reduce the adverse effects of groundwater extraction on surrounding environment, a technical scheme was put forward that set a whole closed curtain with anti-floating anchor in deep foundation pit in thick stratum with abundant water.The static equilibrium and seepage stability conditions were used to analyze the mechanical characteristics of the water stop bottom curtain. The practical design method of the bottom sealing structure of the deep foundation pit was presented.Combined with its engineering characteristics, the construction method and construction control parameters were proposed.The engineering practice shows that the proposed design and construction method are feasible.