Conventional　biological　denitrification　includes　a　serials　of　biological　reduction　processes　with　nitrate　as　electron　acceptor,　by　the　catalysis　of　corresponding　nitrate　reductase　(NaR),　nitrite　reductase　(NiR),　nitric　oxide　reductase　(NoR)　and　nitrous　oxide　reductase　(N2oR).　The　biochemical　reaction　mechanism　and　kinetics　of　denitrification　are　the　theoretical　foundation　of　biological　nitrogen　removal.　In　order　to　promote　further　development　of　biological　nitrogen　removal,　it　is　necessary　and　significant　to　understand　the　complex　biochemical　reaction　mechanisms　of　biological　denitrification　and　its　electron　flow　and　energy　production　pathway.　This　paper,　through　the　discussion　of　the　complex　mechanisms,　puts　forward　the　complex　biochemical　reaction　process　of　biological　denitrification,　including　many　enzymes　and　various　intermediate　products,　and　involving　electron　flow　(energy　production),　analyzes　the　electron　transfer　model　in　which　electron　transfers　from　NADH　to　terminal　electron　acceptor,　and　the　type　of　energy　production　based　on　the　chemiosmotic　hypothesis　established　by　Peter,　and　also　proposes　to　adapt　integral　and　differential　methods　to　solve　the　kinetics　constant　values　νmax,　NO3,　μDmax,　KS,　NO3-　Fig　1,　Ref　27.