Wood basic densityies of about 100 Populus tomentosa Carr. clones grown in 4 clone testing plantations located in Hebei, Henan, Shandong and Gansu were tested and its inheritance and variation among clones and sites were studied. The results showed that the average wood basic density of the studied clones was 0 4363?g/cm 3 and there was significant difference in wood basic density between clones and sites. The high value of clonal repeatability(0 82～0 91)of wood basic density indicated that the character was under strong genetic control. Correlation analysis showed general significantly negative correlation between growth traits(including diameter at breast height, height, and volume) and wood basic density, although the correlation coefficients varied in a certain degree from one site to another. Studies on wood properties and relationships between tree growth and wood quality are of importance in such fields as wood properties breeding and combined improvement of both growth and wood quality. Wood basic densityies of about 100 Populus tomentosa Carr. Clones grown in 4 clone testing plantations located in Hebei, Henan, Shandong and Gansu were tested and its inheritance and variation among clones and sites were studied. The results showed that the average wood basic density of the studied clones were 0 4363? g / cm 3 and there was significant difference in wood basic density between clones and sites. The high value of clonal repeatability (0 82 ~ 0 91) of wood basic density indicated that the character was under strong genetic control. Correlation analysis showed general significantly negative correlation between growth traits (including diameter at breast height, height, and volume) and wood basic density, although the correlation coefficients varied in a certain degree from one site to another. Studies on wood properties and relationships between tree growth and wood quality are of importance in such fields as wood properties breeding and combined improvement of both growt h and wood quality.