A water soluble polysaccharide BRT was isolated from the stem and the root of wild Boschniakia rossica (in Changbai Mountain). Its molecular weight was estimated by gel filtration to be 50 000. Its total content of sugar was 94% by the phenol\|sulfuric acid method. Gas chromatography(GC) analysis indicated that it was composed of Xyl,Gal,Man,Glc and in the molar ratio of 0\^61∶3 12∶1 00∶3 97. The structure analysis of BRT, partial hydrolysis with acid, periodate oxidation, Smith degradation, methylation analysis,GC, GC/MS were used. The results revealed that BRT is of lowly branched structure. The main chain is made up of Gal and Glc, the inner is (1→6)\|linked\|Gal, the border is (1→6)\|linked\|Glc and (1→4)\|linked\|Glc, some of (1→4)\|linked\|Glc residues are substituted at 3 O. On average, there is 1 branch among 10 main chain residues. The side chain is composed of (1→3)\|linked\|Gal, (1→3)\|linked\|Glc, (1→4)\|linked\|Man and (1→6)\|linked\|Man. The nonreduced end is composed of Xyl and Glc. The main glycosidic link of BRT is of β configurations.
