Abstract: Objective To study the antioxidation of banana peel polysaccharides on D-galactose induced oxidative injury in mice.Methods Mice in treatment groups were or ally given banana peel polysaccharides at the dose of 50,100,200 mg/(kg·bw)respectively.The spleen and thymus gland were separated after 42 days of the treatment to determine their indices.In addition,the malondialdehyde(MDA)contents,superoxide dismutase(SOD)and glutathione peroxidase(GSH-Px)activities in serum and liver were assayed.Results In the dose groups of 100,200 mg/(kg·bw),body weight gain were 5.93±0.68,6.10±0.23,the thymus index were 4.38±0.07,4.86±0.17 and the spleen index were 2.55±0.13,3.09±0.21 with significant increases(P<0.01).The content of MDA significantly decreased and the activtiy of SOD and GSH-Px significantly increased both in serum and liver of mice with oxidative injur y(P<0.01).Conclusion The banana peel polysaccharides have significant antioxidation effect on D-galactose induced oxidative injury in mice.