There have been few studies of the alpine subnival belt flora in the Hengduan Mountains (HM), which host remarkable biodiversity. To extend knowledge of this flora, we examined published florae, herbarium specimens, and field observations (and material) collected by both ourselves and others. In total, 942 seed plant species have been recorded in the belt, representing 168 genera and 48 families. Twenty-four large families (with ≥10 species) are present, represented by 873 species (92.68% of the total). These include Asteraceae, Saxifragaceae, and Brassicaceae (146, 82, and 71 species, respectively). There are also 27 large genera (represented by ≥10 species), collectively contributing 587 species (62.31%) to the flora, including