Abstract: BackgroundDesert-steppe ecotones are key regions for studying plant flora evolution and adaptation mechanisms, yet systematic research on the floristic composition and geographical elements of these regions remains insufficient.MethodsThis study takes the desert-steppe ecotone at the northeastern margin of Ulanbuhe Desert as the research object, with Hatengtaohai National Nature Reserve as the typical study area. Through field investigations and literature collection, vascular plants in the area were surveyed and their floristic composition, geographical elements, and life form characteristics were analyzed. A comparative study was conducted with four other typical nature reserves located in desert-steppe ecotones under similar climatic conditions in China. Results (1) The reserve contains 254 species of wild vascular plants belonging to 147 genera and 42 families, with angiosperms comprising the absolute majority (200 species in 136 genera and 43 families, accounting for 97.55%). Asteraceae, Poaceae, Amaranthaceae, and Fabaceae concentrated 50% of the species resources, and 88 genera containing only one species each accounted for 59.86% of the total genera. (2) The geographical distribution types were dominated by temperate elements (86.44%), with coexistence of pantropical and paleo-Mediterranean elements. (3) Comparative analysis with four ecotone reserves revealed that desert-steppe ecotone plant floras exhibit high similarity, characterized by prominent temperate nature and rich paleo-Mediterranean relict elements.ConclusionsThe research results provide scientific basis for desert plant diversity conservation and ecosystem management.