This work was to examine the antioxidation in vitro and hepatoprotective effects of enzyme-extracted Oudemansiella radiata polysaccharides (En-OPS) on alcohol-induced liver damage in mice. The antioxidant activities were determined according to the scavenging effects of En-OPS on hydroxyl, superoxide, and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals, and the level of reducing power. En-OPS showed hepatoprotective activities on decreasing the serum levels of aspertate aminotransferase (AST), alamine aminotransferase (ALT), and alkaline phosphatase (ALP), as well as hepatic lipid levels of total cholesterol (TC) and triacylglycerols (TG). En-OPS treatment reversed the acute impairment induced by alcohol consumption, including reactive oxygen species (ROS) generation, malondialdehyde (MAD), and lipid peroxide (LPO) elevation; and superoxide dismutase (SOD), GSH peroxide (GSH-Px), catalase (CAT), and total antioxidant capacity (T-AOC) impairment. The En-OPS effectively ameliorated alcohol metabolism by activating alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH), and reducing cytochrome P450 2E1 (CYP2E1) levels. Furthermore, the histopathological observations also displayed that En-OPS could alleviate liver damage. These results indicated that En-OPS could be suitable to be an ingredient of preventing alcoholic liver diseases (ALD). In addition, the preliminary structure characteristics of En-OPS were also analyzed by Fourier transform infrared (FT-IR) spectroscopy and a gas chromatography-flame ionization detector (GC-FID).