The invention discloses a method to synthesize the cation vegetable fiber intensifier with the modified glutelin. The invention comprises the following steps: the grafting reaction of the glutelin andthe substituted diamino compound (with the weight ratio of 1:0.7 to 1:2) is conducted under the catalyzing of the transglutaminase, and then an epoxy compound and the grafted glutelin react with theweight ratio of 0.3:1 to 1:1 to generate the modified glutelin containing the annular quaternary ammonium group.