In　order　to　start　up　an　CANON　process　to　treat　domestic　wastewater,　the　simultaneous　anaerobic　ammonium　oxidation　and　denitrification　process　(SAD)　was　started　up　firstly,　then　the　ammonia-oxidizing　bacteria　(AOB)　was　enriched　by　Simulated　domestic　wastewater　under　low　aeration.　During　the　operation　period,　the　variation　of　ammonia　nitrogen　(NH4+-N)　nitrite　nitrogen　(NO2--N)　and　nitrate　nitrogen(NO2--N　)and　dynamics　activities　of　functional　microbes　were　investigated　to　elaborate　main　factors　for　the　conversion　of　sludge　characteristics　in　the　start-up　process　of　CANON.　The　results　showed　that　the　time　of　both　partial　nitrification　process　and　the　adaptation　to　organic　environment　of　ANAMMOX　bacteria　were　shortened.　The　CANON　process　was　started　up　successfully　after　60days.the　ANR　of　CANON　process　exceeded　93%.　Owing　to　the　short　cycle,　the　ratio　of　ananmmox　bacteria　dynamics　activity　with　heterotrophic　denitrification　bacteria　was　always　within　reasonable　limits　(μNH4+-N/μCOD＞　1.0).　The　pH　of　reactor　was　improved　because　of　the　degradation　of　COD　by　heterotrophic　denitrification　bacteria.　In　addition,　the　selective　inhibition　of　NOB　caused　by　both　free　ammonia　(FA)　during　the　aeration　period　was　the　other　main　factor　for　stable　partial　nitrification.　©　2017,　Editorial　Board　of　China　Environmental　Science.　All　right　reserved.