Abstract: To study the characteristic of the Auricularia auricula root polysaccharide(AARP) and protective effect of AARP on acute carbon tetrachloride-induced liver injury. A water-soluble AARP was isolated by hot-water extraction and 80%(v/v) ethanol precipitation. Based on the calibration with Dextran,AARP had a molecular weight of approximately 8.6×105u. The quantification of monosaccharides of AARP was analyzed using highperformance liquid chromatography. According to the corresponding relationship of peak and migration time,AARP mainly consisted of six kinds of monosaccharides apparently. The mole ratio of mannose,rhamnose,glucose,galactose,xylose and fucose of AARP were calculated as 3.389 ∶0.406 ∶7.003 ∶1.248 ∶1.405 ∶4.86:0.45.The protective effect of AARP on acute carbon tetrachloride-induced liver injury was investigated in mice.Compared with modle control group,treatment with middle(50 mg/(kg·d)) and high(100 mg/(kg·d)) doses of AARP were significantly decreased serum aspartate aminotransferase(AST) and malondialdehyde aldehyde(MDA) levels,increased superoxide dismutase(SOD) activity,and improved hepatic injury in the acute model of liver injury in mice. These results suggest that AARP possesses potent hepatoprotective activity.