Abstract:The species diversity changes of subalpine coniferous forests at different restoration stages in western Sichuan province were studied and the responses of 17 soil factors to the species diversity changes were examined by multiple regression analyses. The results showed that species diversity tended to increase gradually with the growth of plantation ages and the species composition in layers of arbor, shrub and herbs changed accordingly. However, restoration of species diversity in subalpine coniferous plantations was quite slow. Responses of physical and chemical properties of soil to species diversity changes varied in different stands. Apparent density and water content which are closely related to the water conservation function of the soil were improved along with increasing species diversity. The accumulated litters, organic matters, hydrolyzed acid and the contents of Ca, Mg, and P in soil, the indicators that represent soil nutrition, also increased with the increase of species diversity in the layers of arbor and shrub, but the content of K2O decreased with the increase of herbage species diversity. We developed the correlative equations of the above-mentioned 9 soil factors with the species diversity indices. The other 8 soil factors showed no direct linear correlation with the diversity indices. Protecting and increasing species diversity in subalpine coniferous plantations can improve part of the soil nutrients and promote the restoration of ecological functions.