In　this　study,　successful　start-up　of　the　anaerobic　ammonium　oxidation　(anammox)　process　in　a　sequencing　batch　reactor　(SBR)　was　achieved　by　seeding　mixed　activated　sludge　which　included　aerobic　sludge,　anaerobic　sludge,　simultaneous　partial　nitrification,　anammox　and　denitrification　(SNAD)　sludge,　and　anammox　sludge　with　low　activity　at　a　2200:2100:5:2　volume　ratio.　On　day　15,　the　effective　anammox　activity　was　attained　in　SBR,　with　the　specific　total　nitrogen　removal　rate　(SRR)　of　0.214　gNg(-1)　VSSd(-1).　The　total　nitrogen　removal　rate　(NRR)　increased　to　230　gNm(-3)　d(-1)　by　gradually　reducing　the　setting　time　to　10　min.　With　the　nitrogen　loading　rate　(NLR)　up　to　506　gNm(-3)　d(-1),　the　total　NRR　of　the　SBR　reached　433　gNm(-3)　d(-1)　during　stationary　phase.　Candidatus　Brocadia　was　detected　as　predominant　functional　microbes　in　the　anammox　SBR.　The　results　demonstrated　the　feasibility　of　seeding　mixed　activated　sludge　to　start-up　an　anammox　SBR　by　settling　option.