In　order　to　analysis　the　impact　of　different　carbon　source　on　the　performance　and　microbial　community　of　Enhanced　biological　phosphorus　removal　(EBPR)　start-up　period,　4　laboratory　scale　sequencing　batch　reactors　(SBR)　supplied　with　different　carbon　source　were　operated.　SBR1　(fed　with　switched　carbon　source　between　acetate　and　propionate)　quickly　achieved　enhanced　phosphorus　removal　efficiency,　the　phosphate　removal　rate　reached　95%　at　50th　day,　while　SBR2(fed　with　glucose　as　a　sole　carbon　source)　still　remained　about　50%　at　the　same　time.　DGGE　analysis　revealed　the　number　of　major　bands　of　SBR1　and　SBR2　decreased　during　the　start-up　period,　thus　their　microbial　community　were　getting　simpler.　The　quantity　of　populations　of　PAOs　and　GAOs　in　each　SBR　was　detected　with　FISH,　it　was　revealed　that　PAOs　increased　rapidly　in　SBR1　on　27th　d　and　50th　d,　and　finally　reached　57%.　Population　of　PAOs　in　SBR2　reached　20%　on　42th　d　and　kept　stability.　While　only　7%　and　4.5%　appeared　in　SBR3　and　SBR4,　respectively.　This　study　showed　that　different　carbon　source　had　a　significant　impact　on　the　microbial　community　structure　succession,　and　carbon　source　switched　between　acetate　and　propionate　had　significant　advantage　over　glucose　and　waste-water　in　the　EBPR　start-up　period.　©　2012　IEEE.