Abstract: Objective:To study protective effect of corn pollen flavonoids on blood, liver and spleen of imitate space radiation injured in mice.Methods:Mice were randomly divided into 5 groups, include normal control group, negative control group, positive control group, FMP-1 group and FMP-2 group, 10 mice in each group.The mice of positive control group, FMP-1 group and FMP-2 group were administered intragastrically with Rutin (78mg/kg/d) , FMP-1 (78mg/kg/d) and FMP-2 (54mg/kg/d) respectively, normal control group and negative control group were administered intragastrically with deionized water (15mL/kg/d) .The animals of all groups except normal control group were treated by imitate space irradiation after gavage 21d.The radiation dose was 4Gy.24h after irradiation animals were sacrificed.The internal organs, include blood, liver and spleen, were dissected out from each animal and used for biochemical investigations.Results:Compared with the negative control, the SOD and GSH-Px activity of the FMP-1 and FMP-2 groups increased significantly in internal organs (p<0.05) , and MDA levels decreased significantly (p<0.05) .Conclusion:Corn pollen extracts, expecially the crude flavonoids extract, had some ideal protective effect against imitate space radiation injury in mice and might be a ideal natural antioxidant potentially.