The　promoting　effect　on　the　formation　of　granular　sludge　by　inoculating　activated　sludge　in　the　enhanced　process　of　biological　phosphorus　removal　was　studied　in　a　laboratory-scale　sequencing　batch　reactor　(SBR).　The　results　showed　that　the　activated　sludge　kept　in　stabilized　flocculent　state　at　biological　denitrification　stage,　and　the　average　SVI　was　138.9　ml·g-1,　while　at　biological　de-phosphorus　one　the　activated　sludge　flocs　became　granular　sludge　gradually　as　the　performance　of　P　removal　became　better.　The　average　SVI　decreased　to　74.1　ml·g-1　and　the　average　diameter　of　the　granules　was　0.8　mm.　Therefore,　the　biological　phosphorus　removal　process　performed　in　SBR　favored　for　the　formation　of　granular　sludge.　Moreover,　it　was　found　that　a　lot　of　positive　charged　particles　were　formed　with　the　release　of　phosphorus　at　the　anaerobic　stage　in　the　biological　de-phosphorus　process.　These　particles　could　serve　as　the　cores　of　granules　to　attract　the　negative　charged　cells　and　stimulate　the　granulation.　The　granular　sludge　system　of　enhancing　biological　de-phosphorus　have　an　excellent　ability　for　the　removal　of　phosphorus.　The　average　removal　rate　of　P　was　nearly　100%.　©　All　Rights　Reserved.