For　make　full　rational　use　of　the　packed　media　surface,　the　fluent　software　was　used　to　the　section　area　of　the　bio-trickling　filter＇s　inlet　is　enlarged　and　the　outlet　gradually　converged.　The　enlarged　cross-flow　bio-trickling　filter　is　characterized　with　low　pressure　drop　and　uniform　distribution　of　gas　and　spray　liquid.　The　filter　inoculated　with　efficient　Pseudomonas　putida　on　the　ceramic　pellets　was　developed　to　degrade　toluene.　With　inlet　concentration　ranging　from　342　mg/m3　to　690　mg/m3,　at　the　residence　time　of　140　s　and　the　temperature　ranging　from　13.5　°C　to　29.6°C,　8　days　were　needed　to　start　the　filter　and　the　removal　efficiency　of　toluene　was　up　to　85　%.　The　effects　of　nutrient　N,　P　content　was　studied,　which　showed　that　the　improved　type　of　MS　culture　medium　(N:　P　=　5:1)　of　the　microbial　biofilm　play　an　important　role　in　promoting　biofilm　forming.　In　the　stable　operation　stage,　the　temperature　ranging　from　16.5　°C　to　35.7　°C,　when　the　residence　time　is　47　s,　the　removal　efficiency　fluctuates　with　the　inlet　concentration　increases　during　40　days.　When　the　inlet　concentration　is　lower　than　650　mg/m3,　removal　efficiency　is　higher　than　95　%,　and　with　the　inlet　concentration　increases　to　1000　mg/m3,　the　removal　efficiency　decreases　to　84　%.　But　the　efficiency　increases　in　a　short　time　and　residences　in　a　high　level.　When　the　residence　time　is　for　140　s,　93　s,　70　s,　56　s,　47　s,　40　s,　35　s　and　32s　respectively,　and　the　inlet　toluene　concentration　is　about　500　mg/m　3,　the　average　removal　efficiency　is　100　%,　99.5　%,　99.2　%,　96.2　%,　94.1　%,　91.8　%,　91.6　%　and　88.8　%　respectively.　Contamination　and　circulation　fluid　bed　filter　in　the　cross-flow　operation,　circulating　fluid　pH　value　of　7.0　∼　8.0,　the　biofilm　system　can　better　adapt　to　the　changes　of　inlet　toluene　concentration.　©　2010　IEEE.