Abstract:Researches were carried out in an age sequence of Pinus tabuliformis natural secondary forest through field surveys on the spots in the Liaoheyuan Nature Reserve. The community characteristic information was studied using quadrat investigation, and by analysing the floristic feature, the physiognomy characteristics, and the population structure of dominant species of P. tabuliformis natural forest. The study was proposed to provide theoretical basis for the protection and management of natural P. tabuliformis forest. Results showed that: (1) the floristics was abundant in P. tabuliformis natural forest community in the Liaoheyuan Nature Reserve, which was composed of 144 species wild seed plants belonging to 90 genera and 41 families. The appearance of community showed obvious temperate coniferous forest, which characterized by hemicryptophyte plants（60.27%） with mesophyll leaf（82.19%）. North temperate element were plentiful, indicating that the community was closely related to the temperate zone. (2) Outstanding dominant species in the community was P. tabuliformis which formed pure forest of different ages. Small diameter（Ⅰ—Ⅲ） trees were more frequent（75%） than other diameter classes in young forest. The ratio of big diameter trees increased with the growth of P. tabuliformis, and the diameter classes had normal distributions in mature forest. Distribution of height classes and canopy classes in each age group were similar as diameter classes. (3) Seedlings in each age group were abundant, especially in mature forest, accounted for 90%, which reflected that potential regeneration ability in the community was strong, while saplings was small, meaning community regenerative condition was not so well.