Abstract: For 5-year-old Eucalyptus globulus, the optimal liquefaction bark process was explored by analyzing the chemical components of the bark and its liquefaction residue before and after the liquefaction. The results of chemical component determination showed that the contents of cellulose, hemicellulose and lignin of bark were 36.65%, 18.98% and 45.37%, respectively. The contents of benzene-alcohol extractives, hot-water extractives and 1% NaOH extractives were 10.30%, 7.15% and 23.64%, respectively. The content of ash accounted for 7.49%. The liquefaction process showed that the catalytic effect of concentrated sulfuric acid was better than concentrated phosphoric acid. The optimum liquefaction parameters were catalytic of 3% concentrated sulfuric acid, temperature of 160℃ and liquid-solid ratio of 5:1. The liquefaction rate was 82.8% under above optimal conditions. Compared with raw materials, the cellulose content, hemicellulose content and lignin content of liquefaction residue reduced by17.90%, 9.19% and 15.99%, respectively.