Abstract: Inhibition of polysaccharides on sarcoma 180 and the immune response of polysaccharides were studied.Polysaccharides of polystictus versicolor used in this experiment were obtained from its mycelium ( PV -1 ) and culture medium ( PV -4 ) . when the polvsaccharides were administered intraperitoneally in daily dose of 10-100mg/kg to sarcoma 180 bearing mice for 10 to 35 days, it was found to have a faint inhibition. PV - 4 couLd not potentiate the inhibition of cyclophosphamide on sarcoma 180, on the contrary it decreased the effect, when daily dose 200mg/kg of polysaccharides was continued for 3 days, they have caused infant mice to lose the thymus weight but to gain the spleen weight. PV - 1 prolong the time of sleeping induced by pentobarbtal.In the normal mice, as well as in these mice suffering from impaired liver caused by carbontetrachloride, when PV - 1 was administered subcutaneously in dose of 100mg/kg for 7 days, it has been found to enhance the phagocytosis of microphage,Studies of acute toxicity have shown that the LD50 of PV - 1 is 2750 mg/kg, PV - 4is 2883 mg/kg for intraperitoneal administration in mice,