Water soluble polysaccharide (lentinan) was crudely extracted from Lentinus edodes, then purified by the methanol fractionation with polysaccharide solution: methanol(v/v) 1: 0. 5 and 1: 1 respectively named ben 1 and ho 2. subsequently, the deproteinized polysaccharide was refined by gel filtration with Sephadex G-100 named Len 3. The finished products were identified by paper chromatography and gel filtration with Sephadex G-100. The compositions of ten 2 and Len 3 were separated by paper-and gas-chromatography. The results show that Len 2 is composed of mannose and glucose with a molar ratio of 10. 50: 1. 00, but Len 3 is composed of xylose, mannose and glucose with a molar ratio of 0.67:2 .45: 1 .00.