Abstract: Based on investigating data of 10 000 m² of 9 plots,details of phytocoenological characters of the community,such as species structure and community diversity,were provided.The main results are:①vascular plants in the original forest are very divers while neither species in genus or genusin families is scarce.Up to 61.74% of the total genera constitute only one species.Dominant species are unclear in tree layers,and the species with biggest important value may not be those in canopy.Shrub layer are dominant with species ofBambusoideae,Lauraceae,Fagaceae,Myrsinaceae,and herb layer are dominant with species of Urticaceae,Acanthaceae and Dennstaedtiaceae;②differ from the typical evergreen broad leave forest in the same belt,which shrub layer is the highest in all layers of the community,except species richness,Shannon-Wiener index,Simpson index and evenness index of tree layer are the highest,following by shrub layer and herb layer in turn;③The fact that the community has complicated speciescomposition but unclear dominant species may indicate that most of species havebeen survival in the long history and the forest contain much information of what it should have had.It may provide effective reference to afforestation to thelarge rocky desertification areas in similar karst environment in Southwestern China.

Key words: karst, original forest, community character, species diversity