There were vast genetic foundation for basic density (BD), fiber length (FL) and microfibril angle (MFA) in 1-69 poplar x Simon poplar and 1-69 poplar x Nigra poplar F1 clones, and the relationships among the three wood characters were independent, which indicated that it would be possible to select the genotypes with good wood properties that was big in BD, long in FL, close in the rang of microfibril. The variation pattern of wood characters within tree revealed the utilization rate of tree stem. BD was a falling-off in the horizontal change, which was considered as ideal type, FL increased with growth ring and the means of FL reached the standard of medium fiber length stipulated by the International Association of Wood Anatomists, MFA decreased gradually from pith to bark. The variation of the three wood characters in perpendicular direction could not make great influence on vertical utilization rate of tree stem.