In　order　to　efficiently　utilize　carbon　source　of　low　C/N　ratio　domestic　sewage,　two　methods　(reducing　organics　input　and　increasing　carbon　source　consumption　through　denitrification)　were　introduced　through　the　partial　nitritation　SBR.　In　this　study,　five　factors,　i.e.　influent　volume,　drainage　ratio,　aeration　time,　precipitation　time　and　stirring　time　after　aeration　were　investigated　to　assess　the　effect　on　the　utilization　efficiency　of　carbon　source(the　ratio　between　the　quality　of　carbon　source　consumption　through　denitrification　and　the　total　organics　input).　The　results　showed　that　when　the　drainage　ratio　was　decreased　from　50%　to　35%,　the　utilization　efficiency　improved　from　15.1%　to　24.8%;　when　the　aeration　time　was　increased　from　2　h　to　2.25　h,　the　utilization　efficiency　increased　from　24.8%　to　27.5%　and　when　1.5　h　of　stirring　time　after　aeration　was　added,　the　utilization　efficiency　increased　by　3.8%.　Meanwhile,　the　nitrite　accumulation　rate　of　the　effluent　was　94.8%　and　the　NO2--N/NH4+-N　was　1.7,　indicating　that　the　partial　nitrification　was　stably　maintained,　and　the　effluent　was　more　proper　for　simultaneous　anammox　and　denitrification　(SAD)　process.　All　in　all,　the　organics　utilization　efficiency　was　promoted　gradually　through　the　adjustment　of　the　operational　parameters　above,　by　which　the　aeration　energy　for　consuming　organics　was　saved,　and　then　the　multiplication　of　aerobic　heterotrophic　bacteria　was　weakened　which　avoided　striking　the　ammonia　oxidizing　bacteria　(AOB)　effectively,　keeping　the　nitritation　effect　stable.　©　All　Right　Reserved.