The　anaerobic-anoxic　oxidation　ditch　(A(2)/O　OD)　process　is　popularly　used　to　eliminate　nutrients　from　domestic　wastewater.　In　order　to　identify　the　existence　of　denitrifying　phosphorus　removing　bacteria　(DPB),　evaluate　the　contribution　of　DPB　to　biological　nutrient　removal,　and　enhance　the　denitrifying　phosphorus　removal　in　the　A(2)/O　OD　process,　a　pilot-scale　A(2)/O　OD　plant　(375　L)　was　conducted.　At　the　same　time　batch　tests　using　sequence　batch　reactors　(12　L　and　4　L)　were　operated　to　reveal　the　significance　of　anoxic　phosphorus　removal.　The　results　indicated　that:　The　average　removal　efficiency　of　COD,　NH4+,　PO43-,　and　TN　were　88.2%,　92.6%,　87.8%,　and　73.1%,　respectively,　when　the　steady　state　of　the　pilot-scale　A(2)/O　OD　plant　was　reached　during　31-73　d,　demonstrating　a　good　denitrifying　phosphorus　removal　performance.　Phosphorus　uptake　took　place　in　the　anoxic　zone　by　poly-phosphorus　accumulating　organisms　NO2-　could　be　used　as　electron　receptors　in　denitrifying　phosphorus　removal,　and　the　phosphorus　uptake　rate　with　NO2-　as　the　electron　receptor　was　higher　than　that　with　NO3-　when　the　initial　concentration　of　either　NO2-　or　NO3-　was　40　mg/L.