The naturalization of alien plants has attracted extensive attention from ecologists because it has a potential invasion risk for the local ecosystem. Community and population structure reflect the environmental adaptability, population status, stability and development trend of plants, and can provide a reliable basis for judging the naturalization of alien plants. Cydonia oblonga is an ancient fruit introduced and cultivated worldwide for more than 4000 years. It has been introduced to China for more than 2500 years, but there was yet to be reported about the living state of its wild feral population in China. This paper took C. oblonga population of Baozhong Mountain, Hunan, China's only place of wild C. oblonga population, as the research object. We analyzed the species composition and the community structure based on the space-for-time substitution method. We conducted a quantitative analysis of the population dynamic of C. oblonga using a static life table, survival curve, and time-sequence model. The results showed that:(1) There were 20 families, 28 genera and 31 vascular plant species including 16 woody species and 15 herbaceous species in the community. The floristic composition was mainly temperate plants which accounted for 75% of non-cosmopolitan genera in the community. (2) The community showed an obviously hierarchical structure including shrub layer and herb layer. The individuals of shrub species were concentrated in the 0-1.5 m height class, accounting for 81.81% of the total number of individuals. (3) The age-class structure of the community showed a nearly reverse "J" growth curve, and the survival curve was closer to the Deevey-Ⅱ type, indicating the stable renewal potential of C. oblonga population. (4) The survival analysis showed that the growth of the population was characterized by an increase in the early stage, decline in the middle stage, and stabilization in the later stage. Time series prediction showed that the populations of C. oblonga would increase in the future, and the number of seedlings and immature trees would remain stable, indicating its low regeneration capability. According to the results, C. oblonga has been naturalized in China. This research can provide a scientific reference to managing alien plants in the region and further developing and utilizing Cydonia oblonga.