Abstract: Objective To observe the effect of soy protein on anti-oxidation in rats. Methods Two weeks after 24 SPF male SD rats were fed with a common chow followed by experiment diets for 28 days, they were randomly divided into soy protein group and casein group. Different anti-oxidation parameters were measured in serum and liver tissue from rats. Results No significant difference was found in liver tissue levels of T-AOC, GSH-Px, SOD, CAT and MDA and in serum activity of T-AOC, GSH-Px, SOD and CAT between the two groups (P＞ 0.05). The serum MDA level was lower in soy protein group than in casein group (P＜ 0.05). Conclusion Soy protein can improve the anti-oxidation of lipid in rats.