To　investigate　the　impact　of　graphene　oxide　(GO)　under　different　concentrations　(0,　50,　100,　150,　200　mg/L)　on　aerobic　granular　sludge　(AGS)　after　a　single　administered　dose,　the　performance　of　nitrogen　removal,　microbial　enzymatic　activity,　extracellular　polymeric　substances　(EPS),　and　microbial　community　structure　were　analysed　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,　showed　that　high　concentrations　of　GO　have　toxic　effects　on　AGS.　The　microbial　bacteria　responded　differently　to　the　stimulation　of　different　concentrations　of　GO.