Abstract: Research on the change of chemical composition of Chinese fir (Cunninghamia lanceolata) wood before and after carbonization was carried out. The contents of alcohol-benzene solubles, lignin, cellulose, holocellulose and1%NaOH extract of the wood after carbonization at 160,190,220℃ respectively were determined. Results showed: with the rise of carbonization temperature, contents of alcohol-benzene solubles and lignin showed a rising trend; cellulose content showed an overall downward trend. Holocellulose content also showed a downward trend, which is more significat than cellulose. One percent NaOH extract content slightly increased. the higher the temperature, the more serious was the damage of the nutritional substance in wood, the better was wood preservative property, but strength was declined. At lower carbonization temperature, the strength and properties of wood can be better maintained. It should be based on actual needs of the timber to choose temperature of carbonization.

Key words: carbonization of wood, chemistry composition, Chinese fir