Abstract: The leachate from waste incineration plant was treated by anaerobic biological filter. The inoculated sludge was digestion sludge which came from a Continuous Stirred-Tank Reactor（CSTR）. The operating temperature was kept at （37±2） ℃. After biofilm were completly growing well， the reactor operated steadily and continuously for nearly six months. During this period， the treatment effect of the reactor on leachate was studied by monitoring COD， NH3-N， TN， pH， VFA， TIC， VAF/TIC， daily biogas production and CH4 content. The results showed that the removal efficiency of organic pollutants in leachate by anaerobic biological filter was very high. When the inlet COD concentration was 49 000~82 000 mg/L and the outlet COD concentration was 3 000~8 000 mg/L， the removal rate of COD reached over 90%； During the operation of the reactor， the TIC was nearly 10 000 mg/L， and the VFA/TIC was basically maintained at 0.2~0.5， which belonged to the appropriate range of anaerobic reactors. Ammonification was significantly， and NH3-N/TN of inlet（40%~70%） was obviously lower than that of outlet （85%~99%）； Gas production efficiency was high， the daily biogas production could reach 300~400 L， CH4 content was nearly 70%.