Abstract: In order to improve the serviceability of starch phosphate, a series of starch phosphate with different amount of quaternary ammonium groups were prepared by varying the feed ratio of N-(3-chloro-2-hydroxyproply) trimethylammonium to starch phosphate. The influence of cationic modification on ζ-potential, paste viscosity, adhesion to cotton fibers, and film behaviors were evaluated by control tests. The experiment results demonstrated that ζ-potential and viscosity of the modified starch paste increases as the degree of substitution (DS) of cationic groups increases. The modification further improves the adhesion of starch phosphate to cotton fibers. With the increase of the degree of substitution, the adhesion enhances and the elongation-at-break of starch film increases.