This paper deals with some factors affecting on liquor phase acetylation of wood from three species (Pinus massoniana, Populus cathayana, Betuls platyphylla), and the dimension stability and decay resistance of acetylated wood. When acetic anhydride and xylene were used as treating liquorat the volume rate of 1" 1, the optimum reaction temperature was 120℃, and the reaction period was 7 to 11 hours. The antishrink efficiency of aeetylated wood could reach more than 60% when weight percent gain (WPC) was 15% or more The decay resistance of treated wood blocks with WPG of 11.75-17.98% was 3 to 34 times higher than that of the controls.