The　activity　changes　of　anaerobic　ammonia-oxidizing　bacteria　during　the　enrichment　process　was　studied　based　on　the　membrane　bioreactor　(MBR).　Completely　autotrophic　nitrogen　removal　over　nitrite　(CANON)　process　was　started　up　by　constant　aeration　rate.　Simultaneous　denitrification　of　ammonia　oxidizing　bacteria　(AerAOB)　and　anaerobic　ammonia　oxidizing　bacteria　(AnAOB)　by　optimizing　the　intermittent　aeration　and　effectively　inhibiting　the　activity　of　nitrite　oxidizing　bacteria　(NOB),　then　the　simultaneous　nitrification,　anammox　and　denitrification　(SNAD)　process　was　started　up　successfully　by　adding　the　the　carbon　source　(sodium　acetate).　The　results　showed　that　enhanced　the　activity　of　anaerobic　ammonia-oxidizing　bacteria　during　the　enrichment　process　of　anaerobic　ammonia-oxidizing　bacteria　by　continuously　shortening　the　hydraulic　retention　time　(HRT)　and　increasing　influent　nitrogen　loading.　The　average　activity　of　the　anaerobic　ammonia-oxidizing　bacteria　increased　from　0.603mgN/(h•gVSS)　to　8.1mgN/(h•gVSS).　When　the　constant　aeration　rate　was　50mL/min　and　the　intermittent　aeration　(non-aeration　time:aeration　time,　mim/min)　was　4:10,　the　removal　of　ammonium　by　AerAOB　and　AnAOB　accounted　for　58.8%　and　41.2%　of　the　total　ammonium　removal　respectively,　and　the　amount　of　nitrite　nitrogen　oxidized　by　NOB　accounted　for　15.3%　of　the　total　nitrate　nitrogen　production,　successfully　inhibiting　the　activity　of　NOB.　When　the　C/N　ratio　was　0.5　and　the　intermittent　aeration　was　adjusted　to　4:15,　the　nitrogen　removal　rate　in　the　denitrification　process　accounted　for　20.9%　of　the　total　nitrogen　removal　rate,　and　the　nitrogen　removal　rate　in　the　anaerobic　ammonia　oxidation　process　accounted　for　79.1%　of　the　total　nitrogen　removal　rate.　The　purpose　of　synergistic　denitrification　of　AerAOB,　AnAOB　and　denitrifying　bacteria　(DNB)　was　achieved　finally.　©　2019,　Editorial　Board　of　China　Environmental　Science.　All　right　reserved.