Abstract: The antioxidant activity of shaddock peels extract(SPE) in rape oil system and its immunomodulatory effects on normalmice was studied. Grapefruit Skin extract showed significant antioxidant activity in rape oil system at concentration of 500×10-6,and VC had synergistic antioxidant effect to SPE in rape oil system. but when the concentration increased to 1000×10-6 and 2000×10-6, it showed pro-oxidant effect, and SPE can also activate serum SOD and reduce the content of MDA of mice significantly,and the concentration-effect relationship was obvious; It was found that Grapefruit Skin extract (Po,100,200mg/kg•d×7d)can significantly intensify DTH caused by DNFB, and SPE (100mg/kg•d,200mg/kg•d, ×15d) can improve phagocytosingfunction of peritoneal macrophage(PMφ) by 22.94%, 53.96% respectively;

Key words: shaddock peels extract, immunity antioxidant activity