Abstract: This paper, based on the field research, presents an in-depth analysis on species composition and succession of natural vegetation in Gupo Mountains. The research suggests that there are in total 92 species of plants in this region, which belong to 48 genera and 71 families. What's more, with the important value index analysis of dominant population in each succession stage, it is concluded that there is no noticeable variation during each stage(except the stages of herbosa), and that quit a few species are dominant species during two or three succession stages. According to the determination of species diversity in each succession stage, the diversity index changes of these species are evergreen-deciduous mixed forest>evergreen broad-leaved forest>brush community>herbosa community. Besides, from the aspect of species community, the total dominance of plant species and relative frequency of each stage, this paper forecasts and demonstrates the order of succession in each stage based on species diversity by employing certain methods, which include index of succession and degrees of succession.The order of succession in each stage is grass,brush,evergreen-deciduous mixed forest and evergreen broad-leaved forest.

Key words: Gupo Mountains, natural vegetation, community composition succession