[Objective] To investigate antioxidant activities of S.pallidfum polysaccharides(SPPS)in vitro.[Method] H2O2/Fe2+ system,pyrogallol system,LPO system were employed to evaluate SPPS ability to scavenge hydroxyl,LPO and superoxide radical.[Result] 26% hydroxyl radical,80% superoxide radical and 40% LPO could be eliminated by 200 μg/ml SPPS.[Conclusion] SPPS were potential anti-oxidant sources.