In　the　sequencing　batch　reactor　(SBR)　of　treating　real　domestic　wastewater　of　the　ratio　of　drainage　height　and　diameter　(H/D)　being　respectively　1:1　and　5:1　(named　as　A　and　B)　aerobic　granular　sludge　(AGS)　was　cultured,　the　H/D　influence　on　aerobic　sludge　granulation　was　investigated.　B　reactor　only　used　16　days　could　realize　aerobic　sludge　granulation,　and　A　reactor　used　36　days　could　realize　the　granulation.　Both　reactors　were　stably　running　612　cycles　(204　days).　Nitrification　effect　was　good.　Particle　size　distribution,　sludge　morphology　results　showed　that　the　AGS　formed　in　B　reactor　was　greater　than　the　particle　size　of　A　reactor　and　structure　was　denser,　more　stable.　AGS　of　B　reactor　comprised　lots　of　cocci　and　bacilli,　without　filamentous　bacteria;　and　AGS　of　A　reactor　contained　great　amount　of　filamentous　bacteria.　On　this　basis　the　relations　among　H/D,　minimum　settling　velocity　and　design　settling　time　were　probed　into.