Abstract: The aged refuse used was found to have large amount of highly activated microbial community and could be used as a substrate for bioreactor. The experiment of treating leachate using secondary aged refuse bioreactors was done in Beijing A-su-wei waste landfill site. It showed that secondary aged refuse bioreactors had excellent and steady removal ability and could adapt to fluctuant leachate admirably. The average concentrations of COD and NH3-N in inflow were 10992 mg/L and 1977 mg/L. When the hydraulic load was 40 L/(m3·d) and loading time was 2 h/d, the average removal rates of COD and NH3-N were 90.9% and 98.9% respectively by the treatment of the system. The average concentrations of COD and NH3-N in treated effluent were about 1001 mg/L and 23.2 mg/L.