In　order　to　realize　rapid　start-up　of　partial　nitrification　by　using　real　domestic　wastewater,　the　experiment　of　three　same　sequencing　batch　reactors　(SBR)　and　the　temperature　is　25°C,　the　dissolved　oxygen　(DO)　is　2.0　mg/L,　the　aerobic　time　is　respectively　T/2,　3T/4,　7T/8(T　was　the　time　from　the　beginning　of　aerobic　to　the　appearance　of　the　＇ammonia　valley＇),　is　conducted　to　investigate　nitrite　accumulation.　The　nitrite　accumulation　ratios　(nar)　were　increased　by　50%,　47%,　70%　in　the　three　reactors　when　the　initiative　pH　value　is　7.7-8.0,　the　nar　increases　fastest　in　which　the　aerobic　time　is　7/8T,　the　partial　nitrification　is　achieved.　The　nar　can　be　increased　by　appropriate　aerobic　time,　by　the　effect　of　the　pH　value　on　the　configuration　of　the　nitrifying　bacteria　and　by　the　inhibition　of　NOB　to　free　ammonia.