In order to simplify the modification process and reduce the cost of wood acetylation,the authors developed a wood acetylation technology using pure acetic anhydride without any catalysts.Effects of reaction temperature and time on weight percentage gain（WPG）of the acetylated Populus ussuriensis wood were evaluated and physical and mechanical properties were tested.Testing results showed that the WPG of the acetylated wood improved with increased reaction temperature and time.Density and anti-swelling efficiency（ASE）of the acetylated wood improved with increased WPG.Effects of the acetylation on modulus of rupture（MOR）and modulus of elasticity（MOE）in static bending were insignificant.Fourier transform infrared（FTIR）analysis indicated that hydrophilic hydroxyls of chemical components of the acetylated wood were replaced by acetyls and hydrophobic esters formed after acetylation,which explained why dimensional stability of the treated wood was improved.