Abstract: Objective To study anti-fatigue effect and biological mechanism of soybean minor peptides(MW300～700Da).Methods Soybean minor peptides was administered to mice in 3 treated groups for 25 days by 3.0,6.0,9.0 g/kg·d)respectively,and the changes of exhaustive swimming time and the bear anoxia ability were measured.Soybean minor peptides was administered to Wister mice in same treated group for 50 days,the activities of superoxide dismutase(SOD)of Hb and liver were measured.Then biochemical index including liver glycogen,blood lactic acid,urea nitrogen were measured intreated groups(One is physiological saline controlgroup).Results Compared with control group,the exhaustive swimming time and bear anoxia ability of administered mice in middle and high dosage group were significantly longer and blood lactic acid content obviously reduces in high dosage group.And there is no significant difference in liver glycogen and urea nitrogen (P<0.05).While the SOD activities of Hb in centre and high dosage group mice obviously increased(P<0.05).And the SOD activities of liver in mice increased,but without significant difference(P>0.05)between groups.Conclusion The soybean minor peptides(MW300-700Da)have a potential anti-fatigue effect and the bear anoxia ability in mice.