The present invention relates to a method for preparing 4,4′-dihydroxy-[1,1′-biphenyl-3,3′-dicarboxylic acid], the method comprising a step for preparing a compound represented by chemical formula 1 by reacting a compound represented by chemical formula 2 with a base according to reaction formula 1. [reaction formula 1] [chemical formula 1] [chemical formula 2] According to the present invention, because use of additional carbon dioxide is unnecessary during the reaction, internal pressure is lowered during same, the reaction can be carried out at a lower temperature, the yield from the synthesis is notably improved as hardening of the resulting substance is absent, and H4dobpdc can be synthesized in large amounts as an additional process for obtaining pure ligands is unnecessary.