Abstarct: A new water-soluble polysaccharide with molecular weight of 95.8 K Da and a specific optical rotation of +136.3° was isolated from the roots of salvia multicaulis by extraction with warm water (70 C°) and purified by DEAE cellulose A 52 and Sephacryl S-400 HR columns, respectively. Total yields of crude and purified polysaccharide were 0.47% and 0.25%, respectively and the total carbohydrate content of purified polysaccharides was about 98.9%, as determined by the phenol- sulfuric acide method. Monosaccharide composition analysis indicated that purified polysaccharides composed of Xyl, Glc, Gal and GlcA in a molar ratio of 2.1: 2.9: 1.0: 1.2, respectively. The structural feature of purified polysaccharides was investigated by combination of optical rotation, partial acid hydrolysis, methylation analysis, periodic oxidation and smith degradation, Fourier transform-infrared spectroscopy (FT-IR) and nuclear magnetic resonance (NMR 1 D and 2 D) spectroscopy. The results obtained from the analyses indicated that main water -soluble polysaccharide of salvia multicaulis roots had a backbone consisting of (1→4)-lixnked α-D-Glcp and (1→4)-lixnked β-D-Xylp and side chains of (1→6)-lixnked α-D-Galp, (1→)-lixnked α-D-GlcpA were attached to the backbone chian at C-6 position of (1→6)-lixnked α-D-Glcp