Abstract: In order to explore the influence of different paraffin wax impregnation on dimensional stability of beech wood, beech wood samples were treated for 2 h or 4 h at 130 ℃ with various paraffin waxes, and the dimension of the samples were recorded subsequently. The results indicated that, with the same temperature and processing time, the dimensional stability of treated samples were improved than the untreated samples. The improvement was even more obvious for impregnation with the high melting point wax. In the dimensional stability measurement, there were large differences among the experimental samples before and after the paraffin wax impregnation. When beech wood samples were impregnated with 85^# microcrystalline wax, the dimension of the samples was most stable. Furthermore, the electron microscopy revealed that, when paraffin wax was impregnated into the surface layer of beech wood, the wax filled the wood cells and other tissues, which could be the reason for the improvement of the wood dimensional stability.