The　effects　of　influent　substrate　concentration　load,　hydraulic　load　and　total　nitrogen　load　on　total　nitrogen　removal　rate　were　compared　in　an　up-flow　ANAMMOX　bio-filter　reactor.　The　deep　region　division　and　bacterial　distribution　in　the　ANAMMOX　bio-film　were　deduced　based　on　the　theory　of　microenvironment　and　the　existence　of　substrate　transfer　gradient.　In　addition,　the　composition　and　distribution　model　was　obtained　for　the　bio-film.　The　results　showed　that　the　maximum　nitrogen　removal　rate　in　the　ANAMMOX　reactor　increased　linearly　as　the　increasing　of　influent　substrate　concentration　load,　hydraulic　load　and　total　nitrogen　load,　respectively.　The　results　indicated　that　the　maximum　of　nitrogen　removal　rate,　influent　hydraulic　load　and　substrate　concentration　of　c(NH　4+-N+NO2--N)　were　12　kg/(m　3·d),　4.79　m3/(m2·h)　and　240　mg·L-1,　respectively.　The　microenvironment　of　the　biofilm,　portrait　grads　distribution　of　the　nitrite　concentration　along　the　depth　of　biofilm　and　the　high　ground　amount　of　the　biomass　made　the　nitrite　resistibility　increase　up　to　130　mg·L-1.　The　biomembrane　system　include　biofacies　and　microenvironment　were　extraordinary　complicated　since　it　affected　by　some　factors　such　as　the　inoculum　of　biofilm,　influent　organic　matters　concentration,　dissolved　oxygen　concentration,　mass　transfer　capability　of　biofilm　and　micro-environment　in　the　bioreactor.　©2010　IEEE.