Rabbits were sensitized by Ginseng polysaccharide then the serum of the rabbits was collected and tested for the cytotoxity activity. The cytotoxic experiment in vitro revealed that the serum has cytotoxity in various degrees against maligant tumor cell lines of human and murine. The partly separated and purified immuned serum was injected into the Ehrlich 180 solid tumors of BALB/C mice. The fascinating hemorrhagic necrosis were find in the solid tumor. The bio-logical and physical feature of purified immuned serum were also analysed. The results indicate that the Ginseng polysaccharide can induce the endogenous production of TNF. The rabbit TNF was stable at 56℃ 30min. This results provided a reliable theoretic basis for the application of Ginseng polysaccharide in anti - tumor treatment.