To　investigate　the　impact　of　graphene　oxide　(GO)　under　different　concentrations　(0,　50,　100,　150,　and　200　mg/L)　on　aerobic　granular　sludge　(AGS)　after　a　single　administered　dose,　the　performance　of　nitrogen　removal,　microbial　enzymatic　activity,　extracellular　polymeric　substances　(EPSs),　and　microbial　community　structure　was　analyzed　in　batch　tests.　The　results　showed　that　the　impact　of　GO　concentrations　on　AGS　was　dose-　and　time-dependent.　Short-term　GO　exposure　could　accelerate　the　nitrification　process　of　AGS,　while　relatively　concentrations　(＞=　100　mg/L)　inhibited　the　process　when　present　for　extended　periods　of　time.　The　microbial　enzymatic　activity　showed　similar　tendency.　The　production　of　lactate　dehydrogenase　release　(LDH)　in　200　mg/L　group　was　increased　48.04%　and　EPS　contents　decreased　30.06%　compared　to　the　control　group　at　30th　day　and　showed　that　high　concentrations　of　GO　have　toxic　effects　on　AGS.　The　microbial　bacteria　responded　differently　to　the　stimulation　of　different　concentrations　of　GO.　Practitioner　points　GO　affected　AGS　system　performance　in　concentration-　and　time-dependent　manners.　The　nitrification　rate　of　AGS　increased　in　the　short　term　and　reversed　over　time.　Long-term　exposure　to　high　GO　concentrations　caused　toxicity　to　AGS.　Different　microorganisms　had　diverse　responses　to　GO　concentrations.