The　effects　of　dissolved　oxygen,　temperature　on　nitrite　accumulation,　and　the　contribution　of　SND　to　total　nitrogen　removal　were　studied.　The　results　showed　that　the　removal　effect　of　Hybrid　MBR　Process　for　late　landfill　leachate　was　good.　In　the　different　stages,　the　samples　were　collected　respectively　from　mixed　liquor　and　biofilm　of　a　MBR.　DNA　was　extracted　from　the　six　samples,　then　16SrDNA　fragments　were　amplified　from　the　total　DNA,　and　then　were　used　for　denaturing　gradient　gel　electrophoresis　(DGGE)　analysis.　The　results　indicated　that　a　noticeable　change　took　place　in　microbial　structure　in　initial　stages.　In　the　whole　operation,　bacterial　community　structures　are　higher.