Abstract: Guandi Mountains, located in the middle of Luliang Ranges, is situated between 37°20'~38°20'N latitude and 110°18'~111°18'E longitude in western Shanxi.There is a typical warm-temperate continental monsoon climate in the mountains, which is cool and arid in winter, however, warm and rainy in summer.It is now known that there are 737 species of seed plants, belonging to 335 genera and 85 families in Guandi Mountains, among which temperate distribution compositons make significant dominant.It has 249 genera and make 85.67% in total genera(excluding cosmopolitan).Based on the analysis of the flora of species and genera and constructive species and dominant of the vegetation in Guandi Mountains, it is indicated that the flora has some typical characteristics of warm-temperate deciduous broadleave forest.Compared with the flora and the vegetation of Taiyue Mountains, the southern segment of Taihang Mountains in Shanxi and Taibai Mountains, Qinling Ranges in Shanxi, there is higher homogeneitive and closely relationship between Guandi Mountains and the southern segment of Taihang Mountains; however, there is some significant differences between Guandi Mountains and Taibai Mountains, Qinling Ranges.

Key words: Guandi Mountains, Seed plant, Flora, Shanxi