Abstract: Study on Taxus chinensis var. mairei population ecology will construct scientific basis for protecting, regenerating and expanding its populations According to statistic in samples of 1600 m2, it is found that the specific composition in community was not complex, for 80 species of 64 genera and of 43 families compose the community flora, averaged 5 species in 100 m2. However, it was almost few species-genera constituted the community, in which the single species-genera accounted for 87. 5% and the rare species genera for 6. 3 %. The results also showed that it was a climax community, as most of the dominant species in arborous layer were stable populations, so that the dominant elements of community floristic were stable. The modular population can be divided into 6 classes which are: 1. seedling(H≤30 cm), 2. sapling (31 cm70 cm). The individual of the last class is always the genet (mother tree). The results show that the development of Taxus chinensis var. mairei populations greatly depends on its modules which sprout on its stem, the types of population size structure are classified into Ｉ. the initial growing type,Ⅱ. the primary type of the growing type, Ⅲ. the growing type and Ⅳ. stable type. When integrating the data of all plots are integrated, the vertical scale of size structure is approximatly pyramidal and the survival curve is slightly sunken but a linear. In other words, it is a stable population.