Enhanced　denitrifying　phosphorus　removal　in　anaerobic-anoxic/oxic　(A2O)　process　is　an　effective　way　to　increase　the　removal　efficiency　of　nitrogen　and　phosphorus　when　treating　low　C/N　ratio　domestic　wastewater.　In　this　study,　a　52.5L　pilot-scale　reactor,　based　on　plug-flow　A2O　configuration,　was　used　to　treat　domestic　wastewater.　In　addition,　the　microbial　population　variation　was　investigated　by　polymerase　chain　reaction-denaturing　gradient　gel　electrophoresis　(PCR-DGGE).　The　results　showed　that　the　microbial　community　structure　and　dominant　bacteria　changed　with　the　variation　of　wastewater　quality　and　operating　parameters.　The　dynamic　change　of　microbial　population　was　consistent　with　the　variation　of　operation.　Sequence　results　of　DGGE　bands　showed　that　the　dominant　bacterial　community　in　the　system　was　Proteobacteria.　Acinetobacter　may　be　responsible　for　the　traditional　biological　phosphorus　removal　in　the　system,　but　it　disappeared　gradually　with　the　enhancement　of　denitrifying　phosphorus　removal.　Uncultured　Chlorobi　bacterium　increased　with　the　enhancement　of　denitrifying　phosphorus　removal　and　it　might　be　the　major　denitrifying　phosphate　accumulating　organisms　(DPAOs)　in　the　system.　©　All　Rights　Reserved.