The invention relates to a preparation method of difluorocarboxylic acid. Difluorocarboxylic acid is hydrolyzed in the presence of organic base to prepare difluorocarboxylic acid. According to the technical scheme provided by the invention, the categories and the quantity of solvents are reduced, and the loss of solvents is reduced; and meanwhile, large-scale emission of acid water is also avoided, and the product cost and the emission of three wastes are reduced while the reaction yield and the content of drugs are increased; and therefore, the method has profound significance for environmental protection.