Niche breadths and overlaps of dominant species in restoring succession processes plant community in Huangpuchuan Watershed were measured using a series of indices proposed by Levins, Shannon-Wiener, and ecological significance of niche breadths and overlaps of each community was analyzed.The results show that each typical community is marked absolutely by one species with the largest niche breadth.Dynamic changes of niche breadth in restoring succession are correspondingly related with the changes of populations.Greater niche overlaps will result in more similarities in ecology and resource use of populations, thus leads to a more intense interspecific competition.Competition is a potential dynamic mechanism promoting different plant communities to the climax community in the watershed.