Bacteria　play　a　key　role　in　the　removal　of　pollutants　and　nutrients　in　constructed　wetlands.　DNA　and　RNA　high-throughput　sequencing　was　used　to　investigate　the　diversity,　metabolic　activity,　and　function　of　bacteria　in　aquaculture　wastewater　and　in　constructed　wetlands　treated　by　different　aeration　levels.　The　results　revealed　that:　a　total　of　4　042　operational　taxonomic　units　(OTUs)　were　detected　in　aquaculture　wastewater　and　constructed　wetland　treatment　groups.　α-Proteobacteria,　γ-Proteobacteria,　and　Bacteroidia　were　the　most　diverse　groups,　and　the　constructed　wetlands　aeration　treatment　increased　the　bacterial　diversity　to　a　variable　extent;　α-Proteobacteria,　γ-Proteobacteria,　Bacteroidia,　and　Actinobacteria　were　the　dominant　groups　both　in　the　DNA　and　RNA　sequencing　results,　and　the　metabolic　activities　of　these　four　groups　were　significantly　affected　by　the　concentration　of　total　nitrogen　(TN)　and　nitrate　nitrogen　(NO3--N)　in　our　study.　According　to　the　FAPROTAX　database,　56　bacterial　functional　groups　were　detected　in　our　study,　mainly　including:　chemoheterotrophy,　aerobic　chemoheterotrophy,　fermentation,　intracellular　parasites,　dark　hydrogen　oxidation,　phototrophy,　photoheterotrophy,　and　nitrate　reduction.　Functions　related　to　the　nitrogen　cycle　were　observed　in　the　results　of　function　annotation,　suggesting　the　important　role　of　bacterial　communities　in　the　removal　of　nitrogen　nutrients　in　constructed　wetlands.　These　results　will　improve　the　understanding　of　bacterial　community　structures　and　functions　during　nutrient　removal　in　aerated　constructed　wetlands.　©　2022,　Science　Press.　All　right　reserved.