Abstract: Liquefaction of wood powder, cellulose and lignin have been studied using ethylene glycol (EG) as liquefaction reagents in presence of sulfuric acid as catalyst, respectively. The results showed that the components of wood (lignin, hemicellulose and amorphous region of cellulose) were easily liquefied compared with crystalline region of cellulose. The liquefaction yield was up to 97%. The ReactIR reaction analysis system with the combination of gas chromatography and mass spectrometry (GC-MS) analysis showed that the liquefied wood products mainly contained EG and its derivatives (diethylene glycol trithylene glycol and dioxane), saccharides, alcohols, aldehydes, ketones, phenols, especially some acids such as formic acid, levulinic acid, oxalic acid and their esters. The structural characteristics of these products indicated that the cellulose can be degraded completely to butyl 4-oxopentanoate, ethyl 3-(2-methyl-1,3-dioxolan-2-yl)propanoate et al., and lignin phenyl propane units were decomposed to aromatic derivatives. Therefore, the liquefied product of wood was a mixture of polyether and/or polyester polyols.