The　Anaerobic/Aerobic/Anoxic　(AOA)　process　based　on　endogenous　denitrification　gained　widespread　attention　in　recent　years　with　the　benefits　of　carbon　saving　and　consumption　reduction.　Nitrogen　is　mainly　removed　via　the　endogeous　denitrification　occurred　in　the　post-anoxic　phase　of　the　AOA　process.　Therefore,　increasing　endogenous　denitrification　rate　(EDNR)　is　the　crucial　to　enhance　the　nitrogen　removal　efficiency.　To　explore　the　methods　to　improve　the　nitrogen　removal　efficiency　of　AOA　process,　the　effects　of　the　anaerobic　duration　and　dissolved　oxygen　(DO)　concentration　in　the　aerobic　phase　on　EDNR　were　investigated　in　this　study.　Results　showed　that　the　EDNR　was　the　maximum　when　the　anaerobic　duration　was　60min　at　the　influent　COD　concentration　of　155.1mg/L.　Under　different　influent　COD　concentration,　the　accumulation　of　polyhydroxyalkanoates　(PHAs)　(a　kind　of　intracellular　carbon)　reached　the　peak　by　controlling　the　appropriate　anaerobic　duration,　and　the　EDNR　was　maximized.　The　EDNR　was　affected　by　excessive　or　insufficient　DO　in　aerobic　phase,　and　the　highest　EDNR　was　achieved　when　DO　was　controlled　at　1mg/L.　The　EDNR　was　increased　by　31.7%　and　18.4%　through　anaerobic　duration　optimization　and　DO　control,　respectively.　This　paper　provided　a　feasible　strategy　to　enhance　the　EDNR　in　the　post-anoxic　phase　of　the　AOA　process,　which　is　conducive　to　the　optimization　of　the　AOA　process　designs　and　operation　strategies.　©　2023　Chinese　Society　for　Environmental　Sciences.　All　rights　reserved.