Abstract:To explore the suitable density for young plantations of Erythrophleum fordii, standard plots were set in 6-year-old Erythrophleum fordii plantation with different densities (2 m×1 m, 2 m×2 m, 2 m×3 m, 3 m×3 m), the characteristics of soil physicochemistry and understory vegetation in young plantation were studied by using soil quality evaluation and grey correlation method. The results showed that the DBH and height of trees under the density of 2 m×3 m were optimal, which were 16.7% and 27.9% higher than the lowest level, and the total porosity, total N, nitrate N and ammonium N contents of soil, as well as shrub and herb diversities also were the highest. After analyzing the correlation between soil physical and chemical properties and plant diversity, soil chemical properties had the greatest influence on shrub and herb diversity. There were significant differences in soil physical and chemical properties and understory plant diversity of E. fordii plantation among different stand densities. Therefore, it was very important to select appropriate density for the sustainable utilization of soil fertility, management and cultivation of plantations.