In　order　to　explore　the　effect　of　different　settling　times　on　aerobic　granulation,　test　was　carried　out　in　a　sequencing　batch　reactor　(SBR),　where　aerobic　granular　sludge　was　rapidly　cultured　through　shortening　settling　time　step　by　step.　The　results　show　that　during　the　procedure,　the　mixed　liquor　suspended　sludge　decreased　gradually,　while,　the　sludge　settleability　was　improved　and　the　inorganic　content　in　the　sludge　increased.　The　sludge　particle　size　differed　under　different　settling　time,　and　the　average　particle　size　has　a　good　negative　correlation　with　the　settling　time.　Moreover,　aerobic　granular　sludge　will　form　if　the　settling　time　is　shorter　than　5　min.　The　polysaccharide　plays　a　main　role　in　sludge　granulation.　During　the　granulation　procedure　in　which　the　settling　time　is　shortened　from　7　min　to　5　min,　the　polysaccharide　in　extracellular　polymeric　substances　(EPS)　increases　from　(140.98±19.54)　mg/g　to　(310.79±50.86)　mg/g.　Shortening　the　settling　time　is　an　effective　strategy　to　cultivate　aerobic　granular　sludge　in　a　sequencing　batch　reactor,　and　the　settling　time　required　for　successful　aerobic　granulation　will　not　be　longer　than　5　min.