Iso-Pr gallate was synthesized by esterification of gallic acid with iso-Pr alc. using chitosan sulfate as catalyst.Through orthogonal experiments, the optimum reaction conditions were obtained as follows : the molar ratio of alc. to acid is 8:1, the quantity of catalyst is 0.8 g, the quantity of toluene is 20 mL, the yield of iso-Pr gallate is up to 90.0%.The results indicated that chitosan sulfate has good catalytic activity and could be used repeatedly.