Four antioxidative flavonoids were isolated from the aerial parts of Hypericum erectum. Their structures were identified as quercitrin (I), isoquercitrin (Ⅱ), hyperoside (Ⅲ) and orientin (IV) on the basis of spectroscopic means. Antioxidative activities for flavonoids $I{sim}IV$ were determined by measuring lipid peroxide using 2-thiobarbituric acid (TBA) method and by evaluation the radical scavenging activity on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. Compound IV, orientin, was found to have strong antioxidative potency.