Abstract: According to field investigation data of plant community on the east slope of Jiuding Mountain in Sichuan, there are 485 species of seed plants that belong to 104 families and 345 genera in this region. It is comparatively rich in species. There are 15 genetic areal-types of seed plants in all. Based on the analysis of the flora, this paper discussed the major characteristics of the flora in the area. The temperate elements have 58.26% of total genera, 201 genera, indicating that the clear nature of temperate zone is the decisive factor of the floristic characteristics. Moreover, the north temperate zone genera 96, is dominant in this area. Tropical of elements have 105 genera, which account for 30.43% of total genera in this region. In addition, the seed plant flora is rich in endemic species,with 17 genera and 18 species endemic to China. At last, the flora is ancient in origin. The above results provide basis for species conservation and vegetation regionalization.

Key words: Plant community, Species diversity, Maintaining mechanism