Phosphorus　release　insufficiency　usually　is　the　main　reason　of　the　degradation　in　enhanced　biological　phosphorus　removal　(EBPR)　process.　Anaerobic-anoxic-aerobic　(A(2)/O)　oxidation　ditch　(OD)　process　treating　the　municipal　wastewater　combined　with　batch　test.　Based　on　the　EBPR　stabilization　of　the　OD　system,　the　activated　sludge　of　SBR　was　taken　from　the　aerobic　zone　of　the　OD,　phosphorus　release　after　acetate　added,　anoxic　phosphorus　uptake　and　denitrification　proceeding　at　different　carbon　sources　was　studied.　The　effluent　activated　sludge　of　the　aerobic　zone　of　the　anaerobic-anoxic-aerobic　oxidation　ditch　process　was　adapted.　5　kinds　of　carbon　source　such　as　acetate,　propionate,　glucose,　ethanol　and　methanol　were　used.　The　main　batch　test　processed　though　batch　test　with　10L　reactor.　The　results　indicated　that:　(1)　In　anaerobic　conditions,　PAOs　released　P　rapidly　with　acetate　or　propionate　acting　as　carbon　sources,　specific　P　release　rate　was　290.5mgP/(gVSS.d)　and　236.7mgP/(gVSS.d)　respectively.　However,　P　released　slowly　when　glucose,　ethanol　or　methanol　acting　as　carbon　source,　the　specific　P　release　rate　was　49.4mgP/(gVSS.d),　38.8mgP/(gVSS.d)　and　8.9　mgP/(gVSS.d)　respectively.　(2)　Whereas　in　anoxic　conditions,　P　release　rate　was　almost　the　same　to　in　the　anaerobic　conditions　if　acetate　or　propionate　act　as　carbon　sources.　But　P　seldom　release　with　glucose,　ethanol　or　methanol　acting　as　carbon　source　in　anoxic　conditions.　(3)　PAOs　utilized　NO3-　to　uptake　P　after　P-release,　if　original　NO3-　was　high　enough,　when　acetate　acts　as　carbon　source.