The N-[(4-bromo-3,5-difluorine)-phenyl]maleimide was synthesized with maleic anhydride and 4-bromo-3,5-difluoroaniline via the solvent azeotropic method, using p-toluene sulfonic acid as the catalyst and toluene / DMF as the mixed solvent. The chemical structure of product was confirmed by means of FTIR, 1HNMR and 13HNMR methods. The synthesis process was optimized, and the suitable conditions were found as follows( based on 38.6 mmol 4-bromo-3,5- difluoroaniline)，amount of p-toluene sulfonic acid 0.8778 g, n(maleic anhydride) : n(4-bromo-3,5- difluoroaniline) = 1.2, amine reaction time 1.5 h, cyclization reaction time 2 h, with a yield of 92.6 %.