Abstract:The wood density of 17 species by means of modified wood densitiometer was first reported in China. The results showed that wood density components,such as average wood density, average earlywood density, average latewood density, the maximum wood density, the minimum wood density,the gradient of wood density and the variation range of wood density, can be measured rapidly and efficiently by direct scanning using X-ray wood densitiometer,which was successful been modified and reequiped on a set of X-ray diffractometer (Model D-max3B). This equipment and measurement method are strongly recommanded by the authors for its power in wood properties genetic improvement.