本文分析和探讨了３．５年生尾叶桉种群密度与胸径、树高、立木单株材积、林分蓄积量及冠幅的作用规律和相关模型。结果表明，密度与林分蓄积量之间呈紧密的正相关关系；而密度与胸径、立木单株材积、树冠幅等各生长因子之间呈紧密的负相关关系；密度对树高生长的影响不显著。根据冠幅与胸径相关的回归方程，应对目前生产中常用造林密度作适当调整。 This paper analyzed and discussed the rules and related models of population density and DBH, tree height, stand volume per plant, stand volume and crown width of 3.5-year-old Eucalyptus urophylla. The results showed that there was a close positive correlation between the density and stand volume, while the density had a close negative correlation with the growth of DBH, stand volume and canopy width. The effect of density on the height growth of tree height Not obvious. According to the regression equation between the crown width and the diameter at breast height, we should make appropriate adjustments to the current planting density.