The exopolysaccharides of Ganoderma lucidum(GLEP) extracted from the fermentation broth after removing protein by Sevage and protease digestion procedures, were applied to a column of DEAE-cellulose(OH- form), and eluted stepwise with distilled water, sodium hydrogen carbonate (0.1 mol/L, 0.3 mol/L, 0.5 mol/L successively) and 0.1 mol/L sodium hydroxide. Five fractions were obtained, and the main fraction was known as GLEP-I, furthermore subjected to chromatography on a column of SepharoseC1-6B, eluted at a flow rate of 30 mL/(cm2.h), the relative viscosity of sample solution of 1.5. Two fractions, GLEP-IFr1 and GLEP-IFr2 with a ratio of 3.8:1, were obtained. Molecular weight of GLEP-IFr1 and GLEP-IFr2 was estimated to be 38,000 and 22,000 Dalton respectively by Membrane Osmometer. The animal test showed that GLEP-IFr1 could inhibited the growth of Sarcoma 180 tumor in mice. The average inhibition ratio was 57.4% (i.p. 10 mg/kg for 10 days). The result of immunological activity showed that GLEP-IFr1 could significantly improve macrophage cytophagy.