Abstract: This is an experiment using a new two-stage fermentation technique to treat pig dung in an anaerobic sludge-bed filter at medium temperatrue. Two 100-litre uncovered acidizing containers and one 100-litre sealed methane-producing container are used for this experi-ment.In the methane-producing container, a three-phase separator and brushes used as fillers are installed inside the container.After three years'operation, the results show that the average gas-producing rate of the methane container in volume is 2.5-2.7 m³/ m³ · d. The results of removing organic matters are obvious. The average COD remove rate reached 76.2%.This system is rather convenient to operate. The control effect is good. It resists strong forces created by shock. This is an effective method for treating animal dungs.