Abstract: Floristic composition and biogeographic structure of wild seed plants in the former Jiangxi Wuyishan National Nature Reserve, now incorporated into Wuyishan National Park (Jiangxi Section), were systematically evaluated through field surveys. Statistical analyses focused on species composition, geographic distribution elements, and conservation status, followed by comparative assessment with floras from 10 national nature reserves distributed along the Wuyi Mountain range from south to north. Results documented a total of 1 589 wild seed plant species belonging to 639 genera and 155 families in the study region. Dominant families were defined by representation of at least 20 species, whereas single-species or low-diversity families and genera were prevalent. Floristic composition at the family level was dominated by tropical elements, including 69 tropical families and 45 temperate families, whereas genus-level composition was characterized by temperate dominance, with 317 temperate genera and 249 tropical genera, yielding an R/T value of 0.79. Comparative analyses across the Wuyi Mountains revealed broadly consistent distribution patterns, with proportions of tropical distribution types decreasing from south to north and temperate distribution types showing the opposite latitudinal trend. R/T values similarly declined along the south-north gradient, with northern reserves consistently showing values below 1, and several reserves on the western slope exhibiting lower R/T values than their neighboring northern reserves. The flora of the Jiangxi section included 81 protected wild seed plants (61 genera, 40 families), including two National Class Ⅰ Protected Species, 40 National Class Ⅱ Protected Species, and 39 Jiangxi Province Key Protected Species, with nearly half facing extinction risks to varying degrees. Overall, the region exhibited high species richness, substantial representation of protected taxa, and pronounced floristic uniqueness and regional representativeness. The seed plant flora reflected ancient origins and marked transitional characteristics, with latitudinal and slope-related influences shaping distribution patterns, temperate elements gradually dominating from south to north, and east-west slope differentiation reflecting underlying climatic transitions.