In　this　study,　three　SBR　reactors　R1,　R2,　and　R3　were　set　up　and　operated　using　(A/O)3-SBR　gradient　aeration,　(A/O)3-SBR　constant　aeration,　and　the　conventional　(A/O)-SBR　mode,　respectively.　The　nutrient　removal　performance　and　aerobic　granular　sludge　characteristics　under　these　aeration　modes　were　explored　using　real　municipal　wastewater　as　the　influent　matrix.　The　experimental　results　revealed　that　for　the　R1,　R2,　and　R3　particles　during　the　stable　period,　the　average　removal　rate　of　COD　was　88.68%,　89.05%,　and　88.96%,　respectively,　the　average　removal　rate　of　TN　was　76.97%,　71.99%,　and　64.92%,　respectively,　the　average　removal　rate　of　TP　was　96.28%,　85.05%,　and　78.97%,　respectively,　and　the　proportion　of　denitrifying　phosphorus　accumulating　bacteria　to　phosphorus　accumulating　bacteria　was　25.52%,　19.60%,　and　12.77%,　respectively.　The　results　showed　that　the　operation　mode　of　anaerobic,　aerobic,　and　anoxic　was　more　conducive　to　the　enrichment　of　denitrifying　phosphorus　accumulating　bacteria　(DPAOs),　and　that　the　gradient　aeration　was　more　enriched　than　the　constant　aeration　mode,　which　is　of　great　significance　to　low-intensity　municipal　domestic　sewage　treatment　with　an　insufficient　carbon　source.　At　the　same　time,　the　dissolved　oxygen　in　the　aeration　section　of　R1　was　reduced　step-by-step,　which　improved　the　simultaneous　nitrification　and　denitrification　rates　of　particles　and　the　utilization　rate　of　the　internal　carbon　source,　which　was　beneficial　for　the　efficient　removal　of　TN.　The　particle　size　of　the　three　groups　of　reactors　was　727.368,　815.　072,　and　895.　041　μm　respectively.　As　the　transfer　rate　of　the　matrix　decreased　with　particle　size,　the　microorganisms　in　R2　and　R3　may　have　caused　anaerobic　respiration　to　release　harmful　gas,　thus　damaging　the　particle　structure,　such　that　the　particles　in　R2　and　R3　were　less　dense　than　those　in　R1.　In　addition,　the　PN/PS　values　of　R1,　R2,　and　R3　were　6.31,　5.63,　and　4.83,　respectively,　and　the　EPS　content　(in　terms　of　VSS)　was　103.97,　92.22,　and　76.98　mg•g-1,　respectively,　at　the　time　of　particle　stabilization,　which　revealed　that　the　mode　of　intermittent　gradient　aeration　was　beneficial　to　stimulate　the　secretion　of　EPS.　This　was　especially　the　case　for　the　secretion　of　PN,　which　increased　the　PN/PS　value,　enhanced　the　cell　hydrophobicity,　and　made　the　particles　dense　and　stable.　©　2020,　Science　Press.　All　right　reserved.