On the basis of field vegetation investigation, specimen collection and data query, the list of seed plants in Zayü River Basin was summarized, and the composition, dominant families and genera, floristic geographical components and properties of plant species in the basin were analyzed. The flora of 16 regions was clustered and analyzed by Rlanguage at the genus level, and the relationship between floristic components and property characteristics with other flora was discussed. The results show that: (1) there are 138 families, 689 genera and 2 771 species (including varieties) of seed plants in Zayü River Basin, including 56 species in 12 genera and 4 families of gymnosperms, 2 715 species in 677 genera and 134 families of angiosperms, and 2 270 species in 531 genera and 112 families of dicotyledons in angiosperms. (2) The geographical elements in the area are widely connected. In addition to the world distribution type, the floristic division of families includes 53 families (55.21%) of tropical distribution type and 43 families (44.79%) of temperate distribution type; In the floristic division of genera, all types are distributed, including 396 genera (62.07%) of arealtype and 230 genera (36.05%) of tropical distribution type; The richness of plant species is high, but the endemic components are low. There are no endemic families and only 12 endemic genera. (3) The vertical zonal distribution of vegetation in the basin is obvious, and many ancient relic plants are retained, such as Taxus wallichiana, Abies chayuensis and Pinus yunnanensis, etc; due to the ascending movement of the QinghaiTibet Plateau, it has become the cradle of differentiation and reproduction of new alpine flora components such as Rhododendron, Saxifraga, Gentiana and Primula. (4) The flora of Zayü River belongs to the floristic nature of the transition from tropical component to temperate component in the south of Himalayas, which is more similar to the flora of Mount Everest Nature Reserve.