During the last few years increasing attention has been paid to the exploitation of hemicelluloses as biopolymer resources because they are available in very large amounts in organic wasters from renewable forest and agricultural biomass. The efficient method to prepare the cationic biopolymers based on xylan-rich hemicelluloses from agricultural biomass has been developed in this paper. These biopolymers with cationic functional groups, having many good properties such as solubility, bio-degradation, cationic or ampholytic polymers, were synthesized by the chemical modification of sugarcane bagasse xylan-rich hemicelluloses with CHMAC and preferably with ETA in different media. These biopolymers based on xylan-rich hemicelluloses with the degree of substitution (DS) up to 0.55 could be obtained by varying the molar ratio of ETA or CHMAC to anhydroxylose units in hemicelluloses from 0.5 to 3.0. 13C NMR confirmed that cationic groups were grafted onto the backbone of hemicelluloses. In addition, their applications in papermaking as dry strengthen agent were investigated. It was found that these biopolymers could obviously improve the physical properties of hand sheets formed from old corrugated container pulp fibres. These results mentioned above highlight the remarkable potential for using the hemicelluloses-based biopolymers as wet end additives in papermaking.