Abstract: The Xianju Kuocangshan Provincial Nature Reserve is regarded by experts as a natural plant "gene pool" and "plant museum" in rarely existing in Zhejiang Province. In 2016, a large-scaled forest dynamics monitoring plot was established in the Kuocangshan Mountain with an area of 1 hm², and based on the international protocols, a field survey of plant communities was conducted for the first time and community characteristics of the sampling plot analyzed from the aspects of species composition, flora feature, diameter class structure, and spatial distribution pattern. Results show that a total of 194 species of vascular plants were found and identified belonging to 126 genera and 68 families, in the plot. Among them there were 121 species of 67 genera and 36 families of arbor plants with DBH ≥ 1 cm. Plant families and genera of tropical nature accounted for 66.67% and 59.70% of their respective totals, while plants families and genera of temperate nature accounted for 33.33% and 38.81% of their respective totals. The plot was home to one and two species of wild plant under the national Grade Ⅰ and Ⅱ priority protection, 10 species listed as nearly endangered or higher in endangered level in the Biodiversity Red List of China, one species listed in the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) (Appendix Ⅱ), 53 species unique to China, indicating that merit sound protection and in-depth research, and 23 species, rare and precious (less than 1 ind·hm^-2) accounting for 19.01% of the total number of tree species. Castanopsis eyrei was the highest in importance value (Ⅳ), reaching 8.69%, and followed by Rhododendron latoucheae (6.80%) and Schima superba(5.92%), with mean DBH being 6.95 cm, indicating that most of the trees were low in DBH in this plot. The analysis of spatial distribution pattern shows that different species of plants varied in spatial distribution, but followed certain rules, separately.