［Purposes］ To investigate the effect of mowing on the species diversity and biomass of Cynodon dactylon communities growing at different elevations in the riparian zone of the Three Gorges Reservoir Area (TGRA). ［Methods］ C. dactylon communities in the riparian zones of 160 m and 170 m in the Ruxi River were selected. The effects of elevation and mowing on community biomass and species diversity were studied by using no mowing control, stubble 30 cm, stubble 20 cm, and stubble 10 cm mowing treatments. ［Findings］ Mowing significantly reduced the coverage, density, important value, and aboveground biomass of C. dactylon, and the biomass of C. dactylon decreased more at 170 m elevation. There was an insignificant difference in C. dactylon community biomass under different mowing intensities (except for C. dactylon communities grown at 170 m elevation treated with stubble 30 cm), and the C. dactylon community biomass at 160 m elevation was significantly higher than that at 170 m elevation. The proportion of C. dactylon biomass at 170 m elevation decreased more than that at 160 m elevation, mowing significantly increased the biomass of other species in the community. The mowing treatment significantly increased the Species richness, the Simpson index, the Shannon-Wiener index, and the Pielou evenness index. There was no significant correlation between community biomass and species diversity, but there was a significantly negative correlation between C. dactylon community biomass and species diversity. ［Conclusions］ C. dactylon grown at 160 m elevation were more tolerant of mowing stress than at 170 m elevation in the TGRA, a certain degree of mowing can significantly increase the species diversity of the C. dactylon community.