Eucalyptus grandis W.Hill ex Maiden bark was liquefied in glycerol with two types of catalysts.The chemical components of the residues with respect to temperature were examined to investigate the liquefaction behavior of bark.The results reveal that sulfuric acid was more efficient in converting bark into fragments in glycerol at low temperatures ≤ 433.15 K,equivalent to 160 ℃ than phosphoric acid.The liquefaction order of chemical components was lignin,hemicelluloses,and cellulose.The decrease of liquefaction yields at high temperatures (＞ 453.15 K) catalyzed by sulfuric acid was possibly a result of the recondensation of lignin and/or hemicelluloses.