It　was　studied　that　treating　domestic　saline　wastewater　in　sequencing　batch　reactors,　different　salinity＇s　affection　on　the　specific　nitrification,　denitrification　rate　and　domin　community　in　the　activated　sludge　system.　The　experiment　utilized　three　parallel　SBR　reactors,　the　ratio　of　influent,　aerobic,　anoxia,　sedimentation　and　effluent　time　was　0.17　h,　7　h,　3　h,　1.5　h　and　0.33　h,　the　three　SBR　systems＇　salinity　were　5,　7.5,　10　g/L,　respectively.　The　three　systems　were　operated　for　50days　in　a　steady　state.　The　results　showed　that:　NaCl　salinity　had　higher　inhabitation　to　nitrobacteria　than　to　denitrifier,　NaCl　salinity　had　higher　inhabitation　to　NOB　than　to　AOB,　7.5　g/L　and　10　g/L　systems　performed　short-term　nitrification-denitrification　in　a　short　time.　Nitrite　accumulation　rate　could　be　maintained　above　95%.　With　the　raising　of　salinity,　specific　nitrification　rate　of　three　systems　declined　in　a　steady　state　5　g/L　and　7.5　g/L　systems＇　had　higher　ammonia　removal　rate　in　a　steady　state.　Salinity　of　7.5　g/L　was　a　perfect　salinity　which　could　result　in　short-term　nitrification-denitrification　in　an　activated　sludge　system.