Abstract: Yundingshan Nature Reserve is situated in the middle part of the Lüliang Mountains,Shanxi province.The wild seed plants of Yundingshan Nature Reserve included 926 species,391 genera and 85 families,of which gymnosperms accounted for 6 species,4 genera and 2 families,and angiosperms accounted for 920 species,387 genera,and 83 families (of which dicotyledons included 756 species, 311 genera 72 families and monocotyledons included 164 species, 76 genera and 11 families).The floristic characteristics of seed plants were diversified and complicated in composition, and were dominated by temperate elements (including 275 temperate genera,accounting for 82.08% of all the genera).Among the floristic elements of species,the temperate elements absolutely dominated,which included 566 species accoun-ting for 62.61%;the second were the endemics to China with 306 species,which were the constructive and dominant forest and shrub species of Yundingshan Nature Reserve.The results showed that higher homogeneity and closer relationship in the floristic elements and vegetation components between Yundingshan Nature Reserve and Pangquangou Nature Reserve,less similarity with Wutai Mountains,and the least similarity with Zhongtiao Mountains.Moreover,Glycine soja being under the national first class protection,and Aconitum smithii,Rhodiola rosea and Codonopsis pilosula being under provincial protection were also found during this study.