Abstract: Wood-plastic composites have become an important approach to modify the low-grade and fast-growing wood to the high-grade wood with the excellent performance. The wood-plastic composites were prepared by electron beam irradiation in this paper. The mechanical properties and water absorption of the modified wood were tested. The results show that the poplar and China fir can be modified to enhanced wood after impregnated with the modified liquid which contains methyl methacrylate as the main body and irradiated by the electron beam for the total irradiation dose of 50 kGy. The density and the compressive strength parallel to grain of the enhanced wood are improved by 70%-160% compared with the original. The flexural strength and bending elastic modulus increase by 14%-70%, and water absorption in 24 h decreases from 67%-85% to 11%-25%. The above results indicate that the basic mechanical properties of woodplastic composites prepared from fast-growing wood such as poplar are close to the level of high-quality mahogany.