Abstract: To investigate the structure change and movement status of molecule in wood caused by different reagents, the dynamic viscoelastic properties of Chinese fir wood treated by NaClO₃, DMSO, DEA-SO₂-DMSO and non-treated wood under the fiber saturated point, temperature from -100-10℃ at frequencies between 0.5 and 10 Hz were examined by DMA. We draw the following conclusions:①It is observed that there are two stress relaxation processes in the temperature range of -100-10℃,α-relaxation process at around -30℃ and β-relaxation process at around -100℃.②The higher the frequency value is,the higher loss modulus E″peak temperature value is. The value of storage modulus E' decreases as the temperature rises.③In α-relaxation process, the value of activation energy of DEA-SO₂-DMSO-treated wood specimens is the highest, DMSO-treated wood specimens is the second, the value of activation energy of NaClO₃-treated wood specimens and that of non-treated wood specimens are the lowest, and the two values are very close.④The rotational motion of the adsorbed water molecules is the main reason that lead to the α-relaxation process of wood. The β-relaxation process is due to the motions of the methylol groups of the cell-wall polymers in the non-crystalline region.