The invention relates to a construction method for dismounting a space special-shaped large-tonnage steel beam bracket. The construction method comprises the following steps: (1) a pier-side bracket is split into an upper layer and a lower layer, namely a bracket and a support, and the bracket is positioned at the upper end of the support; (2) a plurality of continuous jacks are erected on a bridge deck and connected with the bracket through steel strands; (3) the support is disassembled; and (4) the bracket is dismounted after being lowered to the ground through the continuous jacks. The construction method provided by the invention has the advantages that the hoisting weight is heavy; the construction space is small; the construction with multiple high-altitude operations is converted into ground construction; the construction difficulty is greatly reduced; the construction efficiency is improved; and the construction risk is reduced.