Using　actual　domestic　wastewater　as　the　research　object,　nitrogen　compounds　and　their　combinations　were　added　to　different　nitrification　(partial　nitrification,　full　nitrification)　processes　to　investigate　nitrous　oxide　(N2O)　emission　and　its　nitrification　mechanisms.　The　presence　of　influent　NH4+　was　the　driving　force　of　N2O　emission　during　nitrification.　Compared　with　full　nitrification,　NO2-　in　partial　nitrification　more　readily　generated　N2O　by　denitrification.　Under　the　proportional　gradient　of　NH4+-N:NO2--N/NO3--N,　30:0,　20:10,　10:20,　and　0:30,　total　N2O　emissions　during　partial　nitrification　were　2.81,　11.30,　65.20,　and　11.67　times　greater　than　the　total　N2O　emissions　during　full　nitrification.　Full　nitrification　was　more　beneficial　to　N2O　emission　reduction.　This　provides　a　control　strategy　for　N2O　emission　reduction　in　wastewater　treatment　processes　under　the　background　of　reducing　the　production　of　greenhouse　gases.