During the application of 3 kinds of quaternary ammonium salts such as didecyl dimethyl ammonium chloride, didecyl dimethyl ammonium acetate and didecyl dimethyl ammonium propionate composed with copper to Poplar （ Populus ussuriensis ） wood, it was found that the above all had good anti leachability under low temperature conditions. According to leaching rate valuation, the results showed that the fixation of FFJ 2 was the highest among that of the three preservatives when chemical concentration was 0.5% and temperature was 15 ℃. However, the preservatives also had a negative effect on the wood surface causing the treated wood to have a blue color.