The Hengduan Mountains (HDM) constitute one of the world’s richest biodiversity regions and are designated as a top-tier priority for ecological conservation. Vegetation investigations can help with the design and implementation of biodiversity conservation in this region. Here we present the HDM-Plot, a plot-based vegetation dataset compiled from 314 plots surveyed during four campaigns between 2022 and 2024, spanning major vegetation types from lowland dry-hot valleys to alpine areas in altitudes of 754–4,932 m. Each plot records detailed species-level information, including scientific name, growth form, life form, abundance, plant height, diameter at breast height or at base, crown width, and coverage, along with geographic coordinates and hierarchical vegetation classification. In total, the dataset comprises 14,113 individual records belonging to 1,127 species from 379 genera and 117 families. The dominant families are Rosaceae (133 species), Ericaceae (93), Fabaceae (66), Asteraceae (63), and Fagaceae (37), and the dominant genera are <em>Rhododendron</em> (75), <em>Berberis</em> (34), <em>Cotoneaster</em> (30), <em>Salix</em> (24), and <em>Quercus</em> (22), with composition varying among vegetation types. Growth forms are mainly composed of shrubs (46.0 %), trees (27.3 %), and herbs (23.6 %). Herbs are dominated by perennial (92.1 %), shrubs are mainly deciduous broadleaf (59.7 %), and trees are primarily deciduous broadleaf (46.8 %) and evergreen broadleaf (41.6 %). Species richness exhibits a unimodal pattern with a mid-elevation peak, while growth forms and life forms show clear elevational changes. Floristically, temperate (54.1 %) and tropical (35.4 %) areal-types are predominant. 314 plots can be assigned to three vegetation formation groups, 18 vegetation formations, 142 alliance groups, 209 alliances, 238 association groups, and 299 associations. The HDM-Plot dataset provides an updated and standardized baseline for quantitative analyses of mountain vegetation, biodiversity assessment, and vegetation classification and mapping in southwestern China. Such information can be future used in the revisions of China’s vegetation classification scheme<em> </em>and<em>Vegegraphy of China</em>. The dataset is available through the National Tibetan Plateau/Third Pole Environment Data Center (Jin et al., 2026; <a href="https://doi.org/10.11888/Terre.tpdc.303394" target="_blank" rel="noopener">https://doi.org/10.11888/Terre.tpdc.303394</a>).