The Hengduan Mountains region of the northwestern Yunnan is located at a transition-al zone from the Qinghai-Xizang plateau to the Yunnan-Guizhou plateau, with severe erosion and deep gorges. The vertical zonation is very conspicuous here.Sub-tropical montane semi-evergreen and evergreen broad-leaf forest, temperate montane mixed forest, cool temperate montane coniferous forest, subalpine shrubby meadow, alpine subnival belt and alpine nival belt, as well as low valley shrubs with subtropical and arid climate may be identified.The regional differentiation of the vertical zonation features a transition from east to west as well as from south to north. It is closely correlated with changes of the temperature and moisture.