Abstract: A Three generation of Populus deltoids ×P.cathayana was used to study the genetic variation of basic wood properties and the results showed that:wood specific gravity and fiber length have major gene effects of quantitative traits and the heterosis of those traits exist in F2 population; the other way round,fiber width and microfibril angle have polygene effects of quantitative traits.High negative correlations were found between fiber width and specific gravity,fiber width and ratio of length to width. High positive correlations wrer found between fiber length and fiber width,fiber length and width and ratio of length to width.And correlations were not found between fiber length and microfibril angle,fiber width and ratio of length to width.This research can provide reference for pulp wood breeding and selecting of poplars.