Antioxidant activity of Akebia quinata Decne was evaluated. Water extract (0.5 g/50 mL) of flowers and leaves of A. quinata were prepared and total phenol contents and radical scavenging activity of the extracts was determined for antioxidant activity. The total phenol contents of extracts from A. quinata flowers (FAQ) and leaves (LAQ) were $30.05{mu}M;and;20.23{mu}M$, while the radical scavenging activity of FAQ and LAQ were 60.51 % and 52.97%, respectively. In addition, the effect of FAQ and LAQ extract on DNA damage induced by $H_2O_2$ in human lymphocytes was evaluated by comet assay. The FAQ and LAQ showed strong inhibitory effect against DNA damage induced by $200{mu}M$ of $H_2O_2$. These results suggest that water extracts of A. quinata Decne flowers and leaves showed significant (p<0.05) antioxidant activity and protective effect against oxidative DNA damage.