AbstractWe studied the vegetation on six pre-islands (land areas which will become islands as a result of flooding) in the Three Gorges Reservoir with a focus on plant species richness for each community. A total of 28 community types were found on these pre-islands, comprising of 12 hassocks, 7 shrubs, and 9 forests. The results showed that natural vegetation was characterized by intense degradation, implied low vegetation cov-erage, restricted distribution of forests, low community diversity and high ratio of ruderal community types. The species richness of wild vascular plants on the six pre-islands was 126, 157, 175, 189, 242, and 254, re-spectively. The average species richness was 42.9 for forest, 15.96 for shrub, and 17.89 for hassock commu-nities. In all hassock communities, species richness was high in ruderals but was low in typical degraded hassocks. Species richness was generally low in all shrub communities. In the process of secondary succes-sion from conifer-broadleaf forest to broadleaf forest, species richness fluctuated remarkably. Exotic plants significantly impacted the landscape, resulting in degradation of the natural vegetation. These pre-islands are valuable for scientific research, we suggest establishing some nature reserves on them.