Abstract: Based on field investigating and reference collection, the seed plant composition of Liankang Mountain and Xiaoqinling Nature Reserve were studied, the influence of geographical conditions on flora formation and composition were revealed, and the difference and similarity characteristics of both families and genus flora were analyzed with the Czehanowski formula. Results showed that there are 1808 species of seed plants, belonging to 143 families and 716 genera (including various species) in Liankang Mountain, accounting for 94.08%, 79.91% and 61.22% of total families, genera and species in Henan Province respectively; and there were 2004 species of seed plants, belonging to 134 families and 705 genera (including various species) in Xiaoqinling, accounting for 88.16%, 78.68% and 676.86% of that in Henan, respectively. At the level of family and genus, Liankang Mountain and Xiaoqinling flora are mainly tropical and subtropical, and the pan－tropical distribution is dominant, while the temperate distribution occupies a considerable proportion at the same time, showing the common characteristics of the intersection of north and south and the warm and thermal transition. The similarity coefficient of family, genus and species was 92.8%, 81.07% and 61.80% respectively, for adaptation to changing geographical conditions at different latitudes and local habitat heterogeneity, plant groups of the same families and genera appeared widely differentiation at the species level, and which creating the rich plant species resources in both Liankang Mountain and Xiaoqinling.