Persimmon has good health function. To further investigate the antioxidant function in vivo, we set up a model mice with ionizing radiation. IRC mice were divided randomly into six groups, Blank control group, Model control group, VE control group, Low dosage group (G1), Middle dosage group (G2) and High dosage group (G3) respectively. Orally given persimmon extract for 35 days, mice were treated with γ-rays. Our results indicated that pervious administration of the persimmon extraction obviously increased the liver index of the mice. And pathological inspection by microscope suggested that orally given persimmon extraction obviously protected the liver cells of the mice. Further analysis demonstrated that persimmon extraction decreased the MDA content, and increased the SOD and GSH-PX activity in both the serum and the liver in the mice after the Ionizing radiation. Our results suggested the protection role of persimmon extraction by inhibiting the oxidation reaction in vivo.