Disclosed is a 2-substituted-2H-1,2,3-triazole derivative, a compound as represented by formula I or II. Also disclosed is a preparation method of the compound as represented by formula I or II, in particular to a preparation method of 2-substituted-4-bromo-5-chloro-1H-1,2,3-triazole, 2-substituted-4-bromo-5-iodo-1H-1,2,3-triazole, and 2-substituted-5-chloro-1H-1,2,3-triazole-4-carboxylic acid. The preparation methods of the present invention are simple and feasible, and has high yield of the obtained compounds.