A　combined　process　of　a　two-stage　up-flow　anaerobic　sludge　blanket　(UASB),　an　anoxic-aerobic　(A/O)　reactor　and　a　sequencing　batch　reactor　(SBR)　was　used　to　treat　fresh　and　matured　landfill　leachate.　The　operational　mode　of　the　process　was　as　follows:　denitrification　took　place　in　the　first　stage　UASB　(UASB1);　the　chemical　oxygen　demand　(COD)　was　mainly　removed　in　the　second　stage　UASB　(UASB2)　by　methanogenesis;　the　ammonium　nitrogen　was　removed　by　partial　nitrification　in　the　aerobic　zone　of　A/O　reactor;　the　residual　ammonia　nitrogen　was　removed　in　SBR;　and　the　nitrite　and　nitrate　which　was　produced　by　the　nitrification　was　also　removed　in　SBR.　The　experiment　results　show　that　the　COD,　TN　and　NH4+-N　concentrations　of　fresh　leachate　are　about　14.8,　1.8　and　1.3　mg/mL,　respectively;　the　TN,　NH4+-N,　NO2--N　and　NO3--N　concentrations　of　final　effluent　leachate　are　28,　4,　3.4　and　1.9　mg/L,　respectively;　and　the　TN　and　NH4+-N　removal　efficiency　are　more　than　98%.　Meanwhile　the　COD,　TN　and　NH4+-N　concentrations　of　matured　leachate　are　2.5,　3.0　and　2.9　mg/mL,　respectively;　the　TN　and　NH4+-N　removal　efficiency　are　more　than　99%;　the　NH4+-N,　NO2--N　and　NO3--N　concentrations　of　final　effluent　are　less　than　10　mg/L;　the　TN　concentration　of　final　effluent　is　about　26-32　mg/L.