Abstract: Based on the investigation and statistical analysis of vascular plants in Huanglong Protected Area in Sichuan Province, there were 2,313 species of vascular plants, belonging to 154 families and 627 genera. Among them, ferns were composed of there were 141 species, belonging to 36 genera and 22 families; Gymnosperms were composed of 41 species, belonging to 12 genera and 6 families; Angiosperms were composed of and 2,131 species, belonging to 579 genera and 126 families, accounting for 81.82%, 92.34% and 92.13% of the total families, genera and species in the protected area, and angiosperms occupied an absolute advantage. Compared with adjacent protected areas, the plant species here were only lower than Xuebaoding Nature Reserve (minimum elevation: 1600 m), and much higher than that of Wanglang Nature Reserve and Baihe Nature Reserve, which was related to the minimum elevation of the protected area. This study revealed that Huanglong Protected Area served as the core temperate floristic region in the northern section of Hengduan Mountains. The reserve featured a variety of plant communities, ranging from humid and hot valley landforms at lower elevation to alpine scree zones. Floristic analysis at the family level showed that both tropical and temperate distributed families made up large proportions, indicating an obvious transitional floristic nature at the familial rank. At the generic level, temperate distribution types were overwhelmingly dominant (76.67%), with North Temperate genera as the most abundant floristic element in this region (200 genera, accounting for 39.22% of all genera). This fully demonstrated the unique research value of Huanglong Protected Area as the "eastern margin gradient zone of the Qinghai-Tibet Plateau". The flora of vascular plants in this protected area was characterized by the following freatures: a rich floristic composition with distinct dominant families and genera; an ancient origin with prominent primitive traits; a complex composition of areal types, predominantly temperate taxa with distinct transitional features; evident species differentiation; and a rich diversity of protected plant species, including a high number of endemic species. The vascular plants in this protected area represented a key site for regional biodiversity conservation in Sichuan Province and even across China, and occupied an important position within both the provincial and national plant flora.