A　3-dimensional　biofilm　electrode　reactor　(3DBER)　coupled　with　sulfur　autotrophic　denitrification　system　was　developed　by　integrating　with　micro-electrocoagulation　process.　The　novel　process,　namely　MEC-3DBER-S,　was　set　up　to　enhance　the　removal　efficiency　of　nitrogen　and　phosphorus　for　the　effluent　of　low　C/N　ratio　from　municipal　wastewater　treatment　plant　(WWTP).　The　characters　of　MEC-3DBER-S　were　compared　with　that　of　3DBER　under　different　current　conditions.　Moreover,　the　biofilm　denitrifying　bacteria　community　was　also　analyzed　in　MEC-3DBER-S　system　based　on　the　library　of　nirS　gene　cloning　technology.　The　results　indicated　that　the　removal　efficiency　of　nitrogen　and　phosphorus　are　intensified　in　MEC-3DBER-S　process　as　compared　to　3DBER,　especially　the　denitrification　under　the　lower　current　conditions.　Phosphorus　removal　efficiency　could　be　improved　by　the　sponge　iron　corrosion　process　that　was　induced　by　the　function　of　current.　The　nitrogen　and　phosphorus　removal　efficiencies　were　reached　about　75%　and　78%　respectively,　which　were　10%　and　28%　higher　than　that　of　3DBER　under　the　condition　of　C/N=1.5,　HRT=8h,　I=300mA.　In　addition,　it　was　found　that　heterotrophic　denitrifying　bacteria,　hydrogen　autotrophic　denitrifying　bacteria,　sulfur　autotrophic　denitrifying　bacteria　and　iron　autotrophic　denitrification　denitrifying　bacteria　simultaneously　existed　in　MEC-3DBER-S　system,　which　could　respectively　utilize　organic　carbon,　H2,　sulfur　and　Fe2+　as　electron　donors　for　denitrification.　The　denitrification　efficiency　could　be　improved　and　stabilized　by　the　mutual　complementation　of　the　different　electron　donors.　In　the　meantime,　there　would　be　the　physical,　chemical　and　biological　effects　that　were　resulted　in　more　efficient　for　phosphorus　removal　in　the　system.　Thus,　a　higher　nitrogen　and　phosphorus　removal　efficiency　could　be　guaranteed　in　MEC-3DBER-S　process.　©　2016,　Editorial　Board　of　China　Environmental　Science.　All　right　reserved.