Cupressus Gigantea which is one of the endemic and rare species in Tibet, play an important role for ecological environment protection near Yarlung Tsangpo River Valley. This study was based on Cupressus Gigantea of Lang County by using the method of principal component analysis and correlation analysis to explore the relationship between root system and soil environment. The results showed that rock gravel content and rock fracture were the main factors on the shore line and rock hare area respectively; while the main factors of the root architeefure of the terraces and the foot slope were soil fertility, pH, volume weight and natural water content. According to the test, the suitable living environment for Cupressus Gigantea was sandy soil, slight alkali and moderate soil water content. The terraces and the foot slope are the ideal areas for exsitu conservation. At the same time, the effects of soil fertility and soil physical properties should be considerd to improve the survival rate of Cupressus Gigantea planting.
