This study aimed to investigate the seed plant diversity and floristic characteristics of Jizu Mountain in Yunnan, to provide a scientific basis for the assessment, development, utilization, and conservation of seed plant resources in this region. Based on the baseline biodiversity survey data of Jizu Mountain collected from 2023 to 2025 (including 43 transects and 36 quadrats) and relevant literature, the APG IV classification system and Wu Zhengyi’s floristic regionalization criteria were applied to analyze the composition of families, genera, and species of seed plants, their floristic geographical elements, and the characteristics of rare and endangered plant resources. The findings revealed that: (1) a total of 1637 seed plant species belonging to 656 genera and 138 families were recorded, with angiosperms accounting for 99.45% and gymnosperms represented by 9 species in 5 genera and 3 families. (2) The floristic composition showed transitional features: at the family level, tropical elements predominated (tropical families/temperate families, R/T=1.68), while at the genus level (R/T=0.79) and species level (R/T=0.23), temperate elements were dominant. There were 704 Chinese endemic species (43.02%) and one species endemic to Jizu Mountain (Roscoea stenophylla). (3) Invasive plant species numbered 35 (2.14%), and 121 rare and endangered plant species were identified, including one nationally first-class protected plant (Taxus wallichiana), 20 nationally second-class protected plants, four key protected plants of Yunnan Province, and one critically endangered species in Yunnan. The Jizu Mountain region in Yunnan exhibits rich seed plant diversity, complex floristic composition, and significant endemism, serving as an important component of the montane flora in western Yunnan. This study provides a scientific basis for the conservation of regional plant resources. Future efforts should focus on strengthening the prevention and control of invasive plants, as well as enhancing in-situ monitoring and protection of rare species.