Changes of soil factors and undergrowth vegetation species diversity indices, as well as their relationship, in the Eucalyptus industrial raw material forests of Yunnan Province are studied through filed investigation and laboratory analysis. Results show that species richness of herb layer is the highest, while Simpson index, Shannon-Wiener index and Evenness index of shrub layer are the highest. Meanwhile, soil moisture contents in different soil layers under the E. grandis×E. urophylla plantation show the order of parent material horizon> illuvial horizon> humus horizon. However, organic matter content, hydrolytic nitrogen, and available phosphorus and potassium decrease with depth and show the order of humus horizon> illuvial horizon> parent material horizon. Correlation analysis shows that species richness, biodiversity index and evenness index of shrub and grass layers are not significantly correlated with soil moisture and organic matter content in any soil layer. The K content of humus layer and Simpson diversity index of herb layer are significantly correlated. It is also true for the relationship between the K content of illuvial horizon and Simpson index of shrub layer. And there is a notable correlation between the N content and diversity index-based evenness index of shrub and herb layers. The soil factors of parent material and the diversity indices of herb and shrub layers are not correlated. The findings from the study may provide a theoretical basis and scientific evidences for the sustainable management of Eucalyptus industrial raw material forests.