The　treatment　of　real　leachate　from　municipal　landfill　with　high　ammonia　nitrogen(NH4+-N)　content　was　studied　by　using　a　combined　process　of　lab-scale　anoxic/anaerobic　up-flow　anaerobic　sludge　bed　(UASB)-A/O.　The　method　for　achieving　and　stabilizing　partial　nitrification　in　the　A/O　reactor　was　also　investigated.　Experimental　results　clearly　showed　that　COD　and　nitrogen　can　be　simultaneously　deeply　removed　with　this　combined　biological　system,　average　COD　and　NH4+-N　have　been　reduced　from　6537　mgL-1　and　2021　mgL-1　in　the　raw　leachate　to　300　mgL-1　and　15.6　mgL-1,　respectively.　For　the　anoxic　UASB　reactor,　the　average　organic　loading　rate　reaches　to　6.5　kgm-3·d-1,　and　its　average　organic　removal　rate　is　5.3　kgm-3·d-1.　The　denitrification　and　methanogenesis　are　simultaneously　conduced　in　the　UASB　reactor,　and　almost　100%　denitrification　has　been　achieved.　A　stable　and　long　term　partial　nitrification　have　been　realized　by　the　cooperative　effect　of　FA　and　FAN,　the　ammonia　nitrogen　has　been　removed　through　the　highly　effective　partial　nitrification　with　above　99%　nitrite　accumulation　rate.　©All　Rights　Reserved.