In　order　to　strengthen　endogenous　denitrification　and　enhance　the　efficient　utilization　of　limited　carbon　sources,　in　this　study,　one　anaerobic/aerobic/anoxic　(A/O/A)　sequencing　batch　reactor　and　three　groups　of　anaerobic/two-stage　short-time　aerobic/anoxic　(A/(O/A)2)　sequencing　batch　reactors　with　different　aerobic　time　allocations　were　implemented　to　assess　sludge　granularity　and　the　enrichment　of　denitrifying　glycogen　accumulating　organisms　(DGAOs)　across　directional　regulation　of　electron　acceptor.　The　findings　indicated　that　the　aerobic　granular　sludge　in　the　two-stage　short-time　aerobic/anoxic　reactor　exhibited　a　more　compact　structure,　superior　sedimentation　performance,　increased　availability　of　electron　acceptors　in　both　anoxic　and　aerobic　phases.　Furthermore,　the　capability　of　DGAOs　to　accumulate　endogenous　carbon　sources　was　enhanced.　The　competition　between　denitrifying　polyphosphate　accumulating　organisms　(DPAOs)　and　DGAOs　for　carbon　sources　reached　an　equilibrium　state　within　the　system.　Consequently,　the　system　demonstrated　heightened　endogenous　denitrification　and　nitrogen　removal　rates,　thereby　achieving　profound　nitrogen　and　phosphorus　removal.　Notably,　among　these　reactors,　R2,　featuring　a　two-stage　short　aerobic　time　allocation　of　60minutes　in　the　initial　segment　and　30minutes　in　the　subsequent　segment,　exhibited　optimal　denitrification　and　phosphorus　removal　efficacy.　This　reactor　displayed　the　highest　content　of　DGAOs　and　superior　particle　settling　performance.　During　the　stable　operational　phase,　R2achieved　removal　rates　of　90.52%,　85.71%,　and　92.73%　for　COD,　TN,　and　TP,　respectively.　Additionally,　the　endogenous　denitrification　efficiency　reached　58.59%,　underscoring　its　commendable　pollutant　removal　capabilities.　©　2024　Chinese　Society　for　Environmental　Sciences.　All　rights　reserved.