An　anaerobic-aerobic-anoxic　sequencing　batch　reactor　(AOA-SBR)　using　sludge　fermentation　products　as　carbon　source　was　developed　to　enhance　nitrogen　and　phosphorus　removal　in　municipal　wastewater　with　low　C/N　ratio　(＜4)　and　reduce　sludge　production.　The　AOA-SBR　achieved　simultaneous　partial　nitrification　and　denitrification　(SND),　aerobic　phosphorus　uptake　and　anoxic　denitrification　through　the　real-time　control　and　the　addition　of　sludge　fermentation　products.　The　average　removal　efficiencies　of　total　nitrogen　(TN),　phosphorus　(PO43--P)　and　chemical　oxygen　demand　(COD)　after　145-day　operation　were　88.8%,　99.3%　and　81.2%,　respectively.　Nitrite　accumulation　ratio　(NAR)　reached　99.1%　and　sludge　reduction　rate　reached　44.1-52.1%.　Specifically,　34.4%　of　the　TN　removal　was　carried　out　by　SND　and　57.5%　by　denitrification.　Illumina　MiSeq　sequencing　indicated　that　ammonium-oxidizing　bacteria　(Nitrosomonas)　were　enriched　and　nitrite-oxidizing　bacteria　(Nitrospira)　did　not　exist　in　AOA-SBR.　The　system　demonstrated　potential　to　solve　the　dual　problem　of　insufficient　carbon　source　and　sludge　reduction.