Denitrifying　polyphosphate　accumulating　organisms　(DPAOs)　could　remove　N　and　P　simultaneously　when　exposed　to　sequential　anaerobic-anoxic　conditions.　The　key　factor　of　denitrifying　phosphorus　removal　by　DPAOs　was　the　conversion　and　utilization　of　internal　carbon　source.　To　evaluate　the　effect　of　conversion　and　utilization　of　internal　carbon　source　on　the　removal　of　nitrogen　and　phosphorus,　batch　experiments　were　conducted　with　different　anaerobic/anoxic　reaction　time　using　denitrifying　phosphorus　activated　sludge　taken　from　an　anaerobic/anoxic/oxic　(A2/O)-biological　contact　oxidation　(BCO)　system.　The　results　showed　that　DPAOs　produced　the　highest　amount　of　poly-β-hydroxyalkanoate　(PHA)　and　finished　phosphorus　release　when　anaerobic　reaction　time　was　90min,　while　too　long　anaerobic　reaction　time　(120,　150min)　led　to　the　decrease　of　PHA　and　affected　denitrifying　phosphorus　removal.　Additionally,　the　effect　of　long　anaerobic　reaction　time　on　phosphorus　absorption　was　more　significant　than　that　on　denitrification　by　NO3--N,　and　the　specific　phosphorus　uptake　rate　suffered　a　30　percent　fall　when　extending　the　anaerobic　reaction　time　to　150min.　Under　the　appropriate　anaerobic　conditions,　the　optimal　anoxic　reaction　time　for　nitrogen　and　phosphorus　removal　was　120min.　The　nitrogen　and　phosphorus　removal　couldn＇t　finish　with　a　short　reaction　time　(60min),　while　Gly　was　partially　degraded　with　long　anoxic　reaction　time　(180,　240,　300min),　denitrifying　phosphorus　removal　was　indirectly　affected,　and　it　was　of　no　advantage　to　the　long-term　operation.　Furthermore,　in　a　short　time,　the　impact　of　long　anaerobic　reaction　time　on　the　nitrogen　and　phosphorus　removal　was　greater　than　that　of　long　anoxic　reaction　time.　©　2017,　Editorial　Board　of　China　Environmental　Science.　All　right　reserved.