A　novel　strategy　combining　aerobic　starvation　and　free　ammonia　(FA)　was　proposed　to　achieve　partial　nitrifi-cation　(PN).　The　impact　of　the　combined　strategy　on　nitrifying　bacteria　was　explored　in　a　200-day　experiment.　The　effluent　concentration　of　ammonia　was　below　the　detection　limits　(0.1　mg/L),　and　the　effluent　concentration　of　nitrite　and　nitrate　was　68.12　mg/L　and　3.46　mg/L　without　adding　carbon　source　to　the　artificial　wastewater.　The　nitrite　accumulation　rate　(NAR)　was　maintained　at　90.15%　even　when　the　dissolved　oxygen　(DO)　con-centration　was　1.50　mg/L.　Further　analysis　showed　that　PN　was　achieved　by　selectively　restoring　the　activity　of　ammonia-oxidizing　bacteria　(AOB)　in　nitrifying　bacteria　that　had　lost　their　activity　after　starvation.　The　specific　ammonia　oxidation　rate　(SAOR)　was　46.25　mg　N/g　MLVSS/h,　and　the　specific　nitrate　product　rate　(SNPR)　was　only　0.73　mg　N/g　MLVSS/h　in　the　stable　operation　stage.　The　increase　in　AOB　abundance　(from　2.79%　to　7.13%)　and　the　decrease　in　nitrite-oxidizing　bacteria　(NOB)　abundance　(from　8.75%　to　1.44%)　explained　this　phe-nomenon.　Finally,　the　analyses　on　the　secretion　of　extracellular　polymer　substance　(EPS),　strategies　to　resist　harsh　environments,　and　physical　properties　of　sludge　explored　the　potential　mechanism　and　provided　references　for　applying　the　combined　strategy.