methoxide 20 u00b0 c protecting with argon stirring in speed of 50 r min for 3 hours adding 2 58 g of naphthalic anhydride 24 u00b0 c stirring in speed of 40 r min for 60 hours adding 0 1m hcl until ph 6 ending reaction drying by distillation under 50 u00b0 c recrystallizing with absolute alcohol and processing vacuum drying to obtain a monosaccharide derivative having an end group of carboxyl wherein a yield thereof is 9 8 preparing 20 ml of a first solution containing 1 2 of the monosaccharide derivative having an end group of carboxyl adjusting a ph of the first solution to 6 2 with 0 1m hcl adding the first solution into 50 ml of a second solution containing 3 of hydroxypropyl chitosan and 50 of methanol 26 u00b0 c stirring in speed of 60 r min for 72 hours condensing by evaporation under 50 u00b0 c reducing a volume thereof to 7 ml finally depositing with 100 ml of absolute alcohol processing vacuum filtrating and processing vacuum drying to obtain a product wherein a yield thereof is 56 weight of product weight of chitosan derivative 100 suspending 1 g of galactosamine in 100 ml of methanol adding 0 5 g of sodium methoxide 20 u00b0 c protecting with argon stirring in speed of 60 r min for 3 hours adding 0 64 g of glutaric anhydride and 0 82 ml of a catalyst a of tributylamine in turn 24 u00b0 c stirring in speed of 60.