The invention discloses a plugging construction method for an underground structure in a soft soil area. The plugging construction method for the underground structure in the soft soil area is characterized by adopting a method that the mixed solution of high-permeability modified epoxy resin, oil-soluble polyurethane and water-soluble polyurethane is used, long needle heads and short needle heads are embedded through drilling, the polyurethane is injected by the short needle heads at first, and then the high-permeability modified epoxy resin is injected by the long needle heads; the oil-soluble polyurethane and the water-soluble polyurethane are used for a leaked part in a proportion of (2 to 1): 1; during drilling for the long needle heads and the short needle heads, holes are formed at shallow hole points at intervals of 5-8cm from a gap, and formed slantwise at deep hole points at intervals of 8-10cm from the gap; the arrangement distances of the drilled points are set that deep holes and shallow holes are alternately formed, arranged along the two sides of the gap in a staggered and in the form of a quincunx, and closely arranged at the broken and forked parts of the gap; and drilling dip angles are set that the holes are arranged in a crossing manner and at angles of 45-75 degrees with the section of the gap, the drilled holes and the gap are intersected, and the deep holes penetrate through the gap. The plugging construction method for the underground structure in the soft soil area, which is disclosed by the invention, has the advantages of being simple and convenient to construct, and high in the effect of leakage water plugging for the underground structure in the soft soil area.