Constructed wetlands (CWs) have been used successfully to treat municipal wastewater. However, fewstudies have focused on the microbial community in CWs used for tertiary wastewater treatment. Inthis study, 454 high-throughput pyrosequencing was applied to analyze the bacterial community inunplanted, planted, and litter loaded CWs. Results showed that both plants and litter increased thediversity and abundance of the microbial community in CWs. The effects of plant biomass on the bac-terial community at the phylum level were not pronounced, but the compositions were significantlyaffected at the class and genus levels. Specific comparison down to the genus level revealed that therelative abundances of nitrifier, denitrifier and sulfate-reducing bacteria were positively correlated withthe removal efficiencies of ammonia, nitrate and sulfate observed. Highly functional organization (>70%)of the bacterial communities indicates that only a small group of species played a dominant role in CWs.The presence of plants and litter significantly affected the bacterial composition via alteration of carboncontent (%) and pH values in the gravel matrix. The observation in this study provides useful informationabout the effects of plant biomass on the bacterial community structure, which plays an important rolein the tertiary wastewater treatment process in CWs.