Abstract: Taking the seedling growth performance of 47 half-sib families of Eucalyptus cloeziana introduced from Australia as the research object, the families with good seedling growth traits were screened by seedling stage determination. The results showed that there were significant differences in seedling height and ground diameter among Eucalyptus cloeziana families, and four excellent half-sib families were selected. The heritability of seedling height and ground diameter were 0.97 and 0.95, respectively. There was a very significant positive correlation between seedling height and ground diameter. The genetic coefficients of seedling height and ground diameter were 28.61% and 28.18%, respectively. There were abundant variations among introduced families,, which had great improvement potential.