Abstract: To clarify the variation in chemical components and surface morphology of triploid clones of Populus tomentosa and Cunninghamia lanceolata after liquefaction by phenol,using phosphoric acid as a catalyst,fibers of the two species were liquefied under similar conditions.Both liquefied species were investigated with Fourier Transform Infrared Spectroscopy(FTIR),Nuclear Magnetic Resonance Spectroscopy(NMR),including¹H-NMR,¹³C-NMR and³¹PNMR spectroscopy,and Scanning Electron Microscope(SEM).The analysis results from FTIR and NMR showed that chemical components of liquefied triploid clones of P.tomentosa and C.lanceolata changed greatly.This produced the basic composition units of cellulose and lignin,and meanwhile resulted in more active organic functional groups.This phenomenon suggested that there were reactions of decomposition and phenolation between wood components and phenol during wood liquefaction.Results of SEM analysis showed that there were still some fine woody fragments of un-liquefied residue in both reactants of triploid clones of P.tomentosa and C.lanceolata.Shape and size of the remaining fragments in liquefied wood of the two species were different.