In　this　study,　phosphorus　accumulating　microbial　granules　were　successfully　cultivated　in　a　sequencing　batch　reactor　(SBR)　using　synthetic　wastewater.　The　average　diameter　of　the　granules　was　0.74　mm　and　the　diameter　distribution　fitted　well　with　normal　distribution　with　a　correlation　coefficient　of　0.989.　Good　performance　of　biological　phosphorus　removal　(BPR)　was　obtained　in　the　granular　system.　The　average　phosphorus　removal　efficiency　was　over　94.3%　and　the　level　of　phosphorus　in　the　effluent　was　below　0.50　mg/L　during　300　days　of　operation.　Particle　analysis　showed　that　positive　charged　particles　were　formed　with　the　release　of　phosphorus　in　the　anaerobic　stage.　These　particles　served　as　the　cores　of　granules　and　stimulate　the　granulation.　The　maturated　granules　had　a　well-formed　micropore　structure　with　an　average　pore　width　between　291.5　nm　and　446.5　nm.　The　spatial　distribution　of　phosphorus　decreased　gradually　from　the　surface　to　the　center　of　the　granules.　Smaller　granules　had　a　higher　specific　area,　pore　width　and　phosphorus　removal　activity　than　bigger　granules.　(c)　2009　Published　by　Elsevier　Ltd.