Real　domestic　sewage　was　treated　with　sequencing　batch　reactors　(SBR).　The　aerobic/anoxic　modes　were　alternated　4　times　at　30　and　7　times　at　18　in　a　single-cycle,　respectively,　and　the　ratio　of　aerobic/anoxic　cycles　was　30　min/30　min.　The　influent　concentration　of　ammonia　and　nitrite　was　61.44　mg·L-1　and　0.77　mg·L-1,　respectively.　After　the　experiments　were　run　for　61　and　90　cycles,　the　effluent　of　the　ammonia　was　0.68　mg·L-1　and　1.28　mg·L-1　and　the　removal　rate　for　ammonia　was　98.94%　and　99.57%,　respectively.　The　nitrite　concentrations　were　20.57　mg·L-1　and　20.18　mg·L-1,　and　the　nitrite　accumulation　rate　reached　95.92%　and　99.58%,　respectively.　During　shortcut　nitrification,　the　activity　of　the　ammonia　oxidizing　bacteria　(AOB)　increased　gradually　before　finally　stabilizing　at　100.00%,　however　the　activity　of　nitrite　oxidizing　bacteria　(NOB)　increased　first　and　then　decreased　gradually,　the　activity　of　AOB　exceeded　NOB　at　32　and　74　cycles　respectively,　where　the　AOB　became　the　dominant　bacteria　and　the　activity　of　NOB　was　completely　inhibited　at　61　and　90　cycles.　©　2017,　Science　Press.　All　right　reserved.