The　experiment　of　high　concentration　domestic　sewage　treatment　was　carried　out　by　using　predenitrification　biological　aerated　filter　(BAF)　and　polyurethane　filler.　Under　the　conditions　of　the　hydraulic　loading　is　0.64　m3/(m2·h)　and　reflux　ratio　is　1:1,　the　treatment　effect　of　different　ratios　of　air　to　water　was　studied.　Results　show　that　the　treatment　effect　of　the　device　is　good　and　stable.　When　the　aerobic　section　of　the　gas-water　ratio　is　20:1,　the　effect　of　pollutants　removal　is　the　best,　with　obvious　features　of　simultaneous　nitrification　and　denitrification,　significant　nitrogen　removal　ratio　of　82.96%,　and　effluent　concentration　less　than　10　mg/L.　Sampling　along　the　layer　on　the　aerobic,　results　show　that　the　total　nitrogen　removal　mainly　occurs　at　the　bottom　of　the　reactor　between　0　and　0.6　m,　demonstrating　when　ρ(DO)　is　between　1.5　and　2　mg/L,　the　simultaneous　nitrification　and　denitrification　is　obvious,　and　the　TN　removal　rate　is　remained　more　than　80%.　By　simultaneously　monitoring　changes　in　ORP　values　along　the　layer,　the　ORP　during　the　simultaneous　nitrification　and　denitrification　process　can　send　control　signal　and　respond　stably　and　sensitively.According　to　the　change　of　ORP,　the　aeration　can　be　adjusted　to　save　energy　efficiently.