The invention discloses a deep foundation pit underground drainage pre-buried well grouting plugging construction method. The method is characterized by comprising the following steps of a, manufacturing a plugging circular steel plate according to an inner diameter of the pre-buried well, welding a drain pipe, and making a grouting pipe; b, winding an isolation filler around the outer edge of anupper opening of the pre-buried well; c, adding gravel in a pre-buried well, installing a grouting pipe and gravel to a predetermined position; d, installing the plugging circular steel plate, and welding the plugging circular steel plate to the grouting pipe, the pre-buried pipe; e, the grouting pipe and the drain pipe to be high in height to the underground water level equilibrium position; f, grouting, secondary grouting; g, cutting the grouting pipe, the drain pipe, the pre-buried pipe spare section, roughening the edge structure concrete; and h, and pouring concrete for the second time. The drainage pre-buried well plugging system has the advantages that the structure is simple, the operation is convenient, the engineering quality is safe and reliable, the grouting floral pipe is horizontally positioned at the grouting part of the pre-buried well bottom hole, the average distribution of the slurry during grouting is facilitated, the isolation filling material is arranged, when thespare section steel manufacturing facility is removed, the whole structure of the secondary filling concrete is completely combined after roughed.