The anti-oxidative activity of exopolysacchrides(EPS) isolated from the cultured Cordyceps sinensis in vitro was studied.In vitro trials of antioxidant activities and spectrophotometry were chosen to evaluate the free-radical scavenging activity(O-2·,·OH) and Trolox equivalent antioxidant capacity(TEAC) of five EPS fractions in different systems.The results revealed that these EPS fractions could moderately scavenge O-2·,·OH,ABTS+· radicals.Among them,EPS-1A-F3 had stronger effects on free radicals than others.It has a great potential to be an effective antioxiant for dietary and therapeutic applications.