During the industrial production of canned mushroom (Agaricus bisporus), a large quantity of wastewater is produced. In this study, the wastewater generated during the canning of mushroom was analyzed. From this wastewater, four polysaccharide components (Abnp1001, Abnp1002, Abap1001, and Abap1002) with hepatic-protective activity were isolated by ultrafiltration, DEAE cellulose-52 chromatography and Sephadex G-200 size-exclusion chromatography. Results of ultraviolet spectra analysis and molecular weight determination showed that Abnp1001, Abnp1002, Abap1001 and Abap1002 were uniform with average molecular weights of 336, 12.8, 330 and 15.8kDa, respectively. The monosaccharide composition analysis using gas chromatography (GC) showed that the four fractions were heteropolysaccharides and mainly composed of glucose. Fourier transform-infrared (FT-IR) analysis showed that the isolated fractions were all composed of β-glycoside linkages. Additionally, the potential hepatoprotective activities of these polysaccharides against CCl4-induced hepatic injury in mice were studied. Notably, Abnp1002 and Abap1002 could lower the alanine aminotransferase (ALT) and aspartate aminotransferase (AST) concentrations in serum in a dose dependent manner and reduce the hepatocellular degeneration and necrosis, as well as inflammatory infiltration. These results indicate that these two polysaccharides had protective effects on acute hepatic injury induced by CCl4 in mice and suggest that the polysaccharides extracted from A. bisporus industrial wastewater might have potential in therapeutics of acute hepatic injury.