In　this　study,　activated　sludge,　sponge　packing　and　pall　ring　packing　was　integrated　into　segmented　feed　multistage　anoxic/oxic　(A/O)　reactor　for　treating　low-temperature　wastewater,　the　microbial　characteristics　were　investigated　under　the　stable　removal　efficiency.　The　sludge　concentration　and　environmental　scanning　electron　microscope　images　showed　that　the　biofilm　sludge　concentration　was　lower　than　that　of　activated　sludge,　but　the　biofilm　structure　was　denser.　The　microbial　activity　test　results　showed　that　the　microbial　activity　of　the　mixed　system　was　significantly　higher　than　that　of　the　single　activated　sludge　system.　High-throughout　sequencing　analysis　revealed　that　the　microbial　community　in　the　hybrid　system　was　primarily　dominated　by　Proteobacteria　and　Bacteroidetes,　and　there　were　obvious　differences　among　the　stages　in　the　multistage　A/O　reactor　on　the　biofilm,　the　biofilm　populations　of　different　compartments　were　also　significantly　different.　The　mixed　system　improves　microbial　diversity　and　was　beneficial　to　the　removal　of　pollutants　from　low-temperature　wastewater.