The present invention provides a method for synthesis of 2, 3-difluoro-5-bromophenol, 3,4,5-trifluorobromobenzene is used as a raw material, and the method includes the following steps: (1) alkoxy substitution reaction of the 3,4,5-trifluorobromobenzene and an alcohol in the presence of an alkali, and post-treatment of a reaction mixture after the completion of the alkoxy substitution reaction to obtain 3,4-difluoro-5-alkoxy bromobenzene; and (2) dealkylation of the 3,4-difluoro-5-alkoxy bromobenzene in the presence of a lewis acid, and post-treatment of a reaction mixture after the completion of the dealkylation to obtain the 2, 3-difluoro-5-bromophenol. The method can be used for synthesis of the high purity 2, 3-difluoro-5-bromophenol with shorter reaction steps, a simple operation process, a higher yield and a lower cost.