The vertical distribution, morphology, biomass and aging physiological indicators of fine roots of Castanopsis hystrix Miq.in different ages (7, 14 and 25 years old) and soil depths (0-20 and 20-40 cm) were examined using soil coring method, to better understand the tree growth and development and thus provide scientific basis for sustainable management of C. hystrixplantations. C. hystrixplantations were selected in the Guidong and Guinan, Guangxi Zhuang Autonomous Region. The results showed that fine root length density, root surface area density, biomass, specific surface area, vigor and the contents of soluble sugar and soluble protein of fine roots in the same soil layer significantly increased with the increases of stand age, while specific root length, the contents of free proline and malondialdehyde (MDA) of fine roots significantly reduced. Under the same stand age, specific root length, specific surface area, vigor and the content of osmotic adjustment substances of fine roots enhanced with increasing soil depth, while root length density, root surface area density, biomass and MDA content of fine roots significantly decreased. The interaction between stand age and soil layer had a significant effect on biomass, the contents of soluble sugar, soluble protein and MDA of fine roots. There were significant positive correlations between root length density, root surface area density and fine root biomass and soil factors. In contrast, a significant negative correlation was found for free proline content of fine roots and soil factors. Meanwhile, vigor, soluble sugar and soluble protein content of fine roots were significantly positively correlated with soil water content and available nitrogen concentration. Fine roots of young forest (7 years old) were more prone to senescence, followed by 14 years old stand, and then 25 years old stand. Furthermore, fine roots in the topsoil (0-20 cm) had high metabolism, fast turnover rate and short lifespan.