Catalytic hydrotreatment under supercritical ethanol conditions is an effective method for improving the performance of wood tar. In this study, the physicochemical properties of industrial wood tar were characterized, and the hydrotreatment process of wood tar under supercritical ethanol was investigated. In the presence of Pd/C and H-2, with the reaction temperature of 320 degrees C and the reaction time of 3 h, the amount of light component in wood tar increased significantly from 55 to 77 wt %, the ratio of hydrogen to carbon increased, and the oxygen content decreased from 27 to 20 wt %. During the Pd/C catalytic upgrading process, the composition and distribution of light phenols changed obviously. Dimethoxy phenols tended to react to form monomethoxy phenols, and monomethoxy phenols tended to react to form alkylphenols.