Abstract: The inside forest situation and stability of Davidia involucrata population were studied based on the field survey of microenvironment, distribution pattern and age structure of the species in Xiaoliangshan Mountain, Sichuan Province.The results showed that low seedling density caused by unfavorable microenvironment was one of the most important factors for the poor inside forest situation of the population. In addition, the population could develop into the higher stage smoothly and keep stable in the community for a long period once the seedling bank has been established.Some conclusions can be made that the population size bottleneck effect and founder effect are still to be overcome for the species.Passive protection of the habitat is not enough to keep the species from extinction effectively.Moderate human disturbance without destroying the seed repertory is an effective approach to improve the microenvironment and facilitate the building of seedling reserve, thus then these will benefit the natural regeneration, thus the endangered status of the species can be hampered effectively.We also proposed a small population size hypothesis as endanger mechanism of the species and put forward that gene flow among meta-populations would greatly help the re-flourishing of the species.