To　further　utilize　carbon　source　and　reduce　aeration　energy　consumption,　endogenous　denitrification　reactor　(ED-SBR)　coupled　with　the　low　DO　nitrification　reactor　(LDON-SBR)　were　used　to　treat　low　C/N　domestic　wastewater　without　additional　carbon　sources.　The　operation　mode　was:　anaerobic　(ED-SBR)-aerobic　(LDON-SBR)-anoxic　(ED-SBR).　The　feasibility　of　endogenous　denitrification　coupled　with　the　low　DO　nitrification　was　evaluated　according　to　the　performance　of　ED-SBR/　LDON-SBR　system.　The　results　showed　that　low　DO　concentration　(0.3~0.5mg/L)　maintained　a　stable　nitrification　performance　in　the　LDON-SBR,　and　the　nitrifying　efficiency　reached　up　to　90%.　Meanwhile　low　DO　concentration　enhanced　simultaneous　nitrification　and　denitrification　(SND),　and　the　average　SND　rate　was　29.6%　in　the　LDON-SBR;　In　the　ED-SBR,　the　organic　matter　of　influent　was　stored　as　internal　carbon　source　in　the　anaerobic　period.　The　stored　internal　carbon　source　could　be　used　for　endogenous　denitrification　in　the　next　anoxic　period,　which　reduced　NO3--N　concentration　from　27.3mg/L　to　3.9mg/L　in　the　ED-SBR　with　a　NO3--N　removal　rate　of　86.5%;　In　addition,　the　COD　removal　rate　was　about　80%　in　the　low　DO　nitrification　coupled　with　endogenous　denitrification　system.　©　2019,　Editorial　Board　of　China　Environmental　Science.　All　right　reserved.