Abstract: In order to verify the antioxidant activity of γ-terpinene, a main component of cumin essential, fluorescence intensity, three antioxidases (superoxide dismutase, SOD;glutathione peroxidase, GSH-Px;catalase, CAT) activities, and contents of glutathione (GSH) and malondialdehyde (MDA) were evaluated by cell test and animal study. The results showed that fluorescence intensity in Hep-G2 cell was decreased by γ-terpinene with dose-dependent, which demonstrated that oxygen radical was bonded to γ-terpinene both inside and outside the cells, thus, less oxidative products with fluorescence were accumulated in cells. In the experimental model of oxidative stress induced by H₂O₂ and the animal study, γ-terpinene could significantly increase the activities of antioxidant enzymes (SOD, GSH-Px, CAT) and content of GSH (p<0.05). On the other hand, content of MDA was decreased significantly (p<0.05), which was similar to the results in vivo. Above all, γ-terpinene presented antioxidant activity both in vitro and vivo.