Abstract: This paper analysed the phenotypic and genotypic correlations of the different component parts of the tree crown structure to the growth in the two various systems of Ⅰ-69 poplar × Simon poplar and Ⅰ-69 poplar x Nigra poplar F1 clones, separately, the correlations were coneretely analysed into the direct effects and indirect effects by path-analysis, the ideal crown forms of the various systems were determined, the selection indexes of the growth were computed on the basis above, and the selection results of various character combinations were compared. The growth estimates of the different clones were taken by means of the most reasonable equations of selection indexes, which indicated preliminarily that the several good clones selected during nursery could maintain the rapid-growing properties, because they had reasonable relately tree crown structures.