The　start-up,　efficient,　and　secure　operation　of　Anammox　treating　low　ammonia　sewage,　is　an　important　research　focus.　In　this　study,　a　partial　nitrification-denitrification　coupled　with　simultaneous　Anammox　and　denitrifi-cation　(PND-SAD)　process　was　achieved　in　sequencing　batch　reactor/up-flow　anaerobic　sludge　bed　(SBR-UASB).　The　key　measures　to　maintain　high　efficiency　PND　were:　(i)　controlling　dissolved　oxygen　in　the　SBR　below　0.5　mg/L,　which　is　not　only　conducive　to　PN,　but　also　promotes　the　contribution　of　simultaneous　nitrification　and　denitrification　to　nitrogen　removal;　(ii)　monitoring　the　nitrate　(NO3--N)　of　SBR　effluent　and　discharging　sludge　to　wash　out　nitrate　oxidation　bacteria　when　the　NO3--N　exceeds　1.0　mg/L.　The　nitrite　accumulation　rate　reached　97.6%.　SBR　effluent　and　domestic　sewage　entered　the　UASB.　Although　Candidatus　Brocadia　only　accounted　for　0.8%,　its　contribution　to　nitrogen　removal　reached　76.8%.　In　PND-SAD　system,　the　aerobic　HRT　was　only　3.8　h,　nitrogen　removal　efficiency　up　to　97.3%.