The ethanol extract of Abelmoschus manihot (L.) Medic flowers was separated into four extracts by different polarity solvents sequentially, including petroleum ether extract (PE), ethyl acetate extract (EA), n-Butyl alcohol extract (BA) and aqueous extract (AQ). The protective effects of these four extracts against oxidative injures induced by FeSO4 and H2O2 in mice liver homogenate were investigated by the activities of GSH-Px and ATPase. The four fractions were analyzed by HPLC and DNA protecting activity of the extract with strongest antioxidant capacity was evaluated. The results indicated that at the flavonoids concentration of 300 mg/L, ethyl acetate extract (EA) elevated the activities of GSH-Px by 62.82 U/μg prot in a dose-dependent manner. Aqueous extract (AQ) increased the activities of Na+-K+-ATPase and Ca2+-Mg2+-ATPase by 270.85，232.88 U/μg prot at 300 mg/L and 600 mg/L, respectively. EA was rich in flavonoidsincluding hyperoside (116.19 µg/g ), myricetin (67.70 µg/g ) and quercetin (29.13 µg/g) and was effective in preventing DNA damage dose-dependently. Therefore, the high antioxidant activities of EA may be ascribed to the specific structure and chemical activity of the flavonoids.