A　pilot-scale　biological　filter　was　constructed　to　removal　of　iron,　manganese　and　high　ammonia　simultaneously　from　groundwater.　The　results　indicated　that　the　failure　of　manganese　and　ammonia　oxidation　when　the　influent　ammonia　concentration　was　above　2.0　mg/L　without　extra　aeration.　Oxidation　of　iron,　manganese　and　ammonia　could　be　completed　by　downflow　filtration　with　the　aeration　at　the　bottom　of　the　filter　bed,　while　the　processing　capacity　was　affected　significantly　and　was　not　suitable　for　application　of　the　biofilter.　The　upflow　filtration　with　the　same　aeration　mode　could　also　met　the　oxygen　demands　of　the　oxidation　process,　however,　the　oxidized　iron　and　manganese　were　easily　taken　out　filter　bed,　causing　high　iron　and　manganese　concentration　in　the　effluent.　For　the　upflow　filtration　with　extra　aeration　at　the　bottom　of　the　filter　bed,　the　experiments　demonstrated　that　the　intercepting　capacity　of　filter　was　damaged　significantly　by　disturbance　of　aeration　compared　to　the　case　of　upflow　filtration　without　aeration　and　was　inversely　correlatedwith　the　aeration　intensity.