Constructed　wetlands　(CWs)　usually　exhibit　limits　in　functional　redundancy　and　diversity　of　microbial　community　contributing　to　lower　performances　of　nutrients　removal　in　decentralized　domestic　sewage　treatment.　To　address　this　quandary,　heterotrophic　nitrification-aerobic　denitrification　(HN-AD)　bacteria　was　added　in　tidal　flow　CWs　(TFCWs)　developing　for　nitrogen　(N)　and　phosphorus　(P)　removal.　With　addition　of　HN-AD　bacteria,　TFCWs　could　be　setup　more　rapidly　and　obtained　better　removal　efficiencies　of　66.9%-70.1%　total　nitrogen　(TN),　and　88.2%-92.4%　total　phosphorus　(TP)　comparing　with　control　systems　(TN:　53.9%;　TP:　83.9%)　during　stable　operation.　Typical-cycles　variations　showed　that　TFCWs　with　addition　of　HN-AD　bacteria　promoted　NO3--N　and　NH4+-N　removal　respectively　under　hydraulic　retention　time　(HRT)　of　14　h　and　8　h　with　slight　NO2--N　accumulation.　Activated　alumina　(AA)　coupled　with　HN-AD　bacteria　decreased　P　release　and　relieved　its　poor　removal　performance　in　CWs.　Based　on　metagenomic　taxa　and　functional　annotation,　Pseudomonas　and　Thauera　played　pivotal　roles　in　N　removal　in　TFCWs.　Furthermore,　gradient　oxic　environments　by　8　h-HRT　promoted　co-occurrence　of　heterotrophic　nitrifiers　(mostly　Pseudomonas　stutzeri)　and　autotrophic　nitrifiers　(mostly　Nitrosomonas　europaea.　and　Nitrospira　sp.)　which　potentially　accelerated　NH4+-N　transformation　by　elevated　nitrification　and　denitrification　related　genes　(e.g.　amoABC,　hao,　napA　and　nirS　genes).　Meanwhile,　the　addition　of　HN-AD　bacteria　stimulated　nirA　and　gltD　genes　of　N　assimilation　processes　probably　leading　to　NH4+-N　directly　removal.　The　conceptual　model　of　multi-metabolism　regulation　by　HN-AD　process　highlighted　importance　of　glk,　gap2　and　PK　genes　in　glycolysis　pathway　which　were　vital　drivers　to　nutrients　metabolism.　Overall,　this　study　provides　insights　into　how　ongoing　HN-AD　bacteria　addition　effected　microbial　consortia　and　metabolic　pathways,　serving　theoretical　basis　for　its　engineered　applications　of　TFCWs　in　decentralized　domestic　sewage　treatment.　(C)　2021　Elsevier　B.V.　All　rights　reserved.