Oxidative stress plays an important role in the pathogenesis of lifestyle-related diseases. Lactoferrin antioxidant peptide sequence SVDGKEDLIW has been purified from buffalo milk protein and then synthesized by solid phase synthesis. The antioxidant activity of the synthetic peptide was evaluated in D-Galactose treated Kunming mice. The experiment design included 35 mice that randomly divided into 5 groups named, normal group, G-Galatose model group, D-Galactose + low dose of synthetic peptide (0.1 g/kg body weight), D-Galactose + high dose of synthetic peptide (0.6g/kg body weight) and D- Galctose + vitamin C. After 6 weeks, mice were sacrificed and the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-PX) and malondialdehyde (MDA) in blood, heart, liver and brain of mice were measured. The mice group of high-dose peptide showed significantly (P<0.01) higher liver index (5.89) than that of D-Galactose model group (4.41). The highest SOD activity values of heart, liver, brain and blood were obtained in low-dose synthetic peptide group (212.33, 404.88, 296.26 “U/mg protein” and 28.15 “U/g protein”, respectively). Similarly, low-dose synthetic peptide group showed significantly (P<0.05) higher values of GSH-PX activity. Whereas, MDA contents in heart and whole blood (0.35 and 25.24 “nmol/mg protein”, respectively) were significantly (P<0.05) decreased in the low-dose peptide group. This study emphasizes the antioxidant activity of SVDGKEDLIW in vivo and demonstrates a promising antioxidant capacity of the synthetic peptide derived from lactoferrin of buffalo milk.