Batch　experiments　were　conducted　under　normal　temperature　conditions　to　study　the　generation　of　N2O　in　the　partial　nitrification　process　under　different　dissolved　oxygen　concentrations　and　their　production　pathways.　When　dissolved　oxygen　was　0.5,　1.5,　and　2.5　mg•L-1,　the　proportion　of　N2O　released　into　the　total　nitrogen　input　was　4.35%,　3.27%,　and　2.63%,　respectively.　With　increase　dissolved　oxygen,　the　proportion　of　N2O　released　to　total　influent　nitrogen　was　reduced.　Isotope　measurements　showed　that　when　dissolved　oxygen　was　0.5　mg•L-1,　only　denitrification　by　ammonia-oxidizing　bacteria　(AOB)　produced　N2O.　However,　when　dissolved　oxygen　increased　to　1.5　mg•L-1,　the　activity　of　nitrifying　bacteria　increased,　and　4.52%　of　N2O　was　generated　through　a　hydroxylamine　oxidation　process,　whereas　the　N2O　generated　by　AOB　denitrification　accounted　for　95.48%.　When　dissolved　oxygen　continuously　increased　to　2.5　mg•L-1,　the　proportion　of　N2O　produced　by　hydroxylamine　oxidation　increased　to　9.11%,　and　the　N2O　generated　by　AOB　denitrification　accounted　for　90.89%.　The　change　in　dissolved　oxygen　concentration　affects　the　N2O　production　pathway　in　the　short-cut　nitrification　process,　and　avoiding　excessive　NO2--N　accumulation　can　reduce　the　production　of　N2O.　©　2018,　Science　Press.　All　right　reserved.