Abstract: Based on surveys, statistics and analyses of vascular plants within Huanglong Nature Protected Area in Sichuan Province, a total of 2,313 vascular plant species have been recorded, belonging to 627 genera across 154 families. Among them, there are 141 fern species from 36 genera and 22 families; 41 gymnosperm species from 12 genera and 6 families; and 2,131 angiosperm species from 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 respectively. Angiosperms constitute the absolutely dominant group. Compared with adjacent protected areas, the plant diversity here is second only to Xuebaoding Nature Reserve (minimum elevation: 1600 m), and far higher than that of Wanglang and Baihe Nature Reserves, a discrepancy correlated with the minimum elevation of each reserve. This study reveals that Huanglong Nature Protected Area serves as the core temperate floristic region in the northern segment of the Hengduan Mountains. Its vegetation spans humid and hot valley landforms at low elevations up to alpine scree floras. Floristic analysis at the family level shows that both tropical and temperate distributed families make up large proportions, indicating an obvious transitional floristic nature at the familial rank. At the generic level, temperate distribution types are 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 demonstrates the unique research value of Huanglong Protected Area as the "eastern margin gradient zone of the Qinghai-Xizang Plateau". The vascular plant flora of the protected area possesses the following characteristics: rich floristic composition; prominent dominant families and genera; ancient origin with striking primitive traits; complex phytogeographic elements dominated by temperate taxa with distinct transitional features; evident species differentiation; abundant protected plant species; and rich endemic species. The vascular plant flora of this protected area represents a key site for regional biodiversity conservation in Sichuan and even across China, and forms a vital component of national floras, occupying an important position within the vascular plant resources of Sichuan and the broader Chinese flora.