Abstract: With dimension of 20mm×20mm×20mm, six species of tree (Betulaalbo sinensis, Tilia endochrysea, Zelkova schneideriana, Catalpa fargesii f.duclouxii, Swietenia macrophylla, Tectona grandis) were treated for 4 h and 8 h in order to explore the influence of paraffinoil impregnation on woods dimensional stability. The results showed that, under the conditions of the same temperature and treatment time, the dimensional stability of treated wood was significantly better than untreated one. In moisture measurement, the line swelling rate of treated wood was 9329% lower than the control group, the minimum can reach more than 45%; for different species, there were big differences in the dimensional stability among the treated wood. Tectona grandis is the most suitable for this method.