Paeonia suffruticosa var. spontanea, distributed in a very small area in Shanxi and Shaanxi provinces of China, is an endemic, endangered, and nationally protected species. To assist the protection of this species, the biological and ecological characteristics of its populations were investigated and analyzed. There are eight communities (TWINSPAN result) in which this species is found. It prefers forest communities dominated by Quercus liaotungensis in the warm-temperate climate zone. Its spatial distribution pattern is clumped in all communities. Its populations are expanding in all study areas. Biomass and productivity are closely related to plant age, density, and environmental conditions. The level of sexual reproduction is low, and the main method of reproduction of this species is vegetative propagation. Canopy gaps may be important for the establishment, growth, and reproduction of this species. Based on these characteristics, some suggestions for the conservation management of Paeonia suffruticosa var. spontanea and its environment are discussed.