Abstract: Objective To study antilipemic effect of differently deacetylated flyblow chitosan.Methods The chemical method was used to prepare 72.3%,80.5%,96.1% deacetylated flyblow ehitosan and IR waft;used to identify its structure.Adult male SD rats were randomly divided into five groups：control group、hypercholesterolemia control group、dosage group with 72.3%,80.5%,96.1% deacetylated flyblow chitosan.The rats were fed with ahigh cholesterol diet and were administrated flyblow chitosan continuously for 8 weeks at the same time.Then the blood 1ipid and weight were measured.Results The serum contents of TC、TG、LDL-C in the dosage group were significantly lower than those in hypercholesterolemia control group(P<0.01),the content of HDL-C was significantly higher than that in hypercholesterolemia control group(P<0.01)and the weight in the dosage group was significantly lower than those in hypercholesterolemia control group(P<0.01).Conclusion Flyblow chitosan has distinct preventive effect on hypereholesterolemia,its effect is related to the deacetylation degree.