A portable Li-6400 photosynthesis measuring system was used to explore how Castanopsis tibetana, an precious native species to China, adapts to the environment and to illustrate and determine various photosynthetic characteristics of Castanopsis tibetana. Taking one-year seedling of Castanopsis tibetana from different geographical provenance of Liuyang, Sangzhi, Yongshun Hunan, Jian’ou Fujian and Enshi Hubei, as material, Some photosynthetic parameters were dynamicly monitored. Also, the physiological mechanisms that have resulted in the endan...