Foundation pit drainage system

The utility model discloses a foundation pit drainage system which comprises a retaining wall built on the side wall of a foundation, the side wall of the retaining wall is provided with a water storage tank, the side wall of the upper end of the water storage tank is provided with a vertical groove, the side wall of the vertical groove is connected with a water guide pipe in a sliding mode, and the two ends of the water guide pipe penetrate through the side wall of the vertical groove and extend to the outside. The water guide pipe located at the outer end of the retaining wall is connected with a socketed pipe, water guide plates are connected to the side walls of the two sides of the water guide pipe located in the water storage tank, the two ends of each water guide plate are arranged in an arc shape, and a plurality of water storage holes are formed in the side walls of the two sides of the water storage tank. Water and rainwater permeating from the ground can be collected into the water storage tank in