Objective To study the anti-aging effect of caloric restriction in aged rats. Method Thirty-four male aged SD rats were randomly divided into 3 groups. The experimental groups were given 80% and 60% diet of the control respectively. After 6 months we measured serum SOD,MDA,IL-2,the activity of NO,MAO in brain tissue and apoptosis index of hepatocytes. Results The activities of NO in brain tissue,SOD and IL-2 in serum in experimental groups were significantly higher than those in control group. Serum MDA,MAO of brain tissue and apoptosis index of hepatocytes in experimental groups were lower than those in control. Conclusion Caloric restriction shows anti-aging biological effects in aged rats.