The spatial distribution pattern of plant diversity is one of the important issues in phytogeography and macroecology research. In terms of phytogeographic zoning, Xinglong Mountain Nature Reserve is located at the intersection of Loess Plateau, Qinghai-Tibet Plateau and Mengxin Plateau, and possesses a rich mountainous plant diversity, whose vertical distribution pattern is not yet clear. Through field surveys and related literature collection, the nature reserve can be divided into six vegetation vertical zones: grassland zone (1 800~2 000 m), mountain scrub zone (2 000~2 200 m), subalpine coniferous forest zone (2 200~2 900 m), subalpine dwarf forest zone (2 900~3 000 m), alpine scrub zone (3 000~3 500 m) and alpine meadow zone (>3 500 m). In this paper, the plant richness, life type, zonal composition and phylogenetic structure of each vegetation vertical zone were analyzed with seed plants as the research object. The results showed that: (1) the plant family, genus and species richness showed a unimodal distribution pattern with the elevation of the vegetation vertical zone, reaching a peak in the subalpine coniferous forest zone; Jaccard similarity coefficient was moderately dissimilar and extremely dissimilar among the vegetation vertical zones. (2) The vertical variation pattern of different life types differed, with the proportion of woody plants showing an increasing trend followed by a decreasing trend, while the herbaceous plants showed the opposite pattern of variation. (3) At the genus level, the proportion of tropical components showed a decreasing trend with the elevation of the vegetation zone, while the proportion of temperate components showed an increasing trend. (4) The phylogenetic structure was dispersed in the subalpine coniferous forest zone in the middle and low elevation regions and aggregated in the three vegetation zones in the high elevation region (>2 900 m), indicating that the non-random distribution pattern plays a major role in the community construction mechanism. The results of this study are important for understanding the environmental characteristics and community building mechanism of this mountainous region, and provide a scientific and theoretical basis for plant diversity conservation and rational exploitation of resources.