Successful　application　of　mainstream　anammox　would　be　favorable　for　energy-and　resource-efficient　sewage　treatment.　This　study　presents　a　new　strategy　to　achieve　mainstream　anammox,　which　combined　with　endogenous　partial　denitrification　(EPD)　for　treating　sewage　wastewater.　In　this　EPD-Anammox　system,　nitrite　was　stably　produced　by　EPD　with　a　nitrate-to-nitrite　transformation　ratio　of　80%.　Through　adjusting　the　volume　exchange　ratio　of　EPD-reactor　after　anaerobic　reaction,　a　suitable　NO2--N/NH4+-N　ratio　of　similar　to　1.20　for　anammox　reaction　was　achieved.　Further,　results　showed　a　stable,　high　nitrogen　removal　efficiency　(90%)　with　an　effluent　total　nitrogen　of　5.8　mg　N/L　under　low　C/N　(similar　to　2.9).　Anammox　contributed　49.8%　of　the　overall　nitrogen　removal　owing　to　the　steady　nitrite　supply　from　EPD.　Denitrifying　glycogen-accumulating　organisms　(GAOs,　36.6%)　having　potential　for　endogenous　denitrification　and　Candidatus　Brocadia　(34.6%)　were　respectively　dominated　in　the　EPD-SBR　and　anammox-UASB　and　responsible　for　the　high　nitrite　accumulation　and　anammox　reaction.