Abstract: Objective: To investigate the protective effect of polysaccharide from Crassostrea gigas internal organs ( CGOP) on acute liver injury induced by CCl₄ in mice.Methods: CGOP was analyzed effects of antioxidant action by scavenging DPPH free radical, hydroxyl free radical, ABTS radical and reduction potential. ALT, AST levels in serum and MDA, SOD levels in liver tissues were examined. In addition, pathologic changes were examined by HE staining. Results: CGOP showed antioxidant abilities.And acute hepatic injury protections of CGOP were demonstrated by the fact that increased in activity of liver AST and ALT caused by CCl₄ of mice treated were significantly inhibited while the MDA content was significantly lowered and SOD activity enhanced as well.Histopathological changes induced by CCl₄ were also significantly reduced.The results indicated that CCl₄ acute liver damages could be inhibited by CGOP.It provides the basic data for making better use of oyster resources.