This　research　focused　on　the　enrichment　of　phosphorus　accumulating　organisms　(PAO)　and　glycogen　accumulating　organisms　(GAO)　in　enhanced　biological　phosphorus　removal　(EBPR)　systems-SBR　reactors　fed　with　activated　sludge.　P/C　and　the　carbon　sources　were　considered　as　two　main　factors　to　control　the　enrichment　conditions.　So　high　P/C　and　alternate　acetate　and　propionate　were　supplied　to　PAO,　low　P/C　and　acetate　were　supplied　to　g-GAO,　and　low　P/C　and　propionate　were　supplied　to　α-GAO.　Under　the　suitable　pH,　temperature,　DO　of　the　aerobic　phase　and　load　of　the　influent,　the　enrichment　of　these　three　kinds　of　groups　was　achieved　with　the　results　below:　Accwnulibacter　reached　80%　of　the　total　bacteria,　and　the　efficiency　of　P　removal　was　over　than　98%.　Competibacter　could　reach　90%of　the　total　bacteria,　and　also,　α-GAO　was　a　absolutely　predominant　group　in　its　reactor.　Furthennore,　details　just　like　the　autoclaved　feed　and　the　completely　dissolved　feed　can　affect　the　results　of　the　enrichment　work.