NOVELTY - The dry anaerobic fermentation system comprises a material supplying fermentation tank, a feeding device and a mixing device. Upper and lower parts of the mixing device are connected with the fermentation tank and feeding device. The mixing device and the fermentation tank are connected at a bottom part of the fermentation system. An outer wall of the mixing device and the fermentation tank are fixed together. The feeding device comprises a feeding hopper for passing material and a feeding pump.    USE - The dry anaerobic fermentation system is useful for producing marsh gas (claimed).    ADVANTAGE - The fermentation system is convenient to use, and ensures that the fresh materials are completely and uniformly mixed in a feeding device, thus preventing large flow of materials on the outside of the fermentation tank.    DETAILED DESCRIPTION - The dry anaerobic fermentation system comprises a material supplying fermentation tank, a feeding device and a mixing device. Upper and lower parts of the mixing device are connected with the fermentation tank and feeding device. The mixing device and the fermentation tank are connected at a bottom part of the fermentation system. An outer wall of the mixing device and the fermentation tank are fixed together. The feeding device comprises a feeding hopper for passing material and a feeding pump. An inlet of the feeding hopper is connected with an outlet through a first pipeline. The fermenting tank is connected a lower part of the mixing device through a second pipeline. The pipelines are provided with switch valves, respectively. The inner diameter of the second pipeline to the mixing device is 1:10. Top and bottom parts of the fermentation tank are provided with an exhaust port and a discharging port. A top part of the fermentation tank is connected with an exhaust port through a third pipeline provided with a third switch valve. The stirring device is connected with an upper part of a heat exchanger through a fourth pipeline provided with a fourth switch valve. An air compressor is connected with the fermentation tank through the fourth pipeline for conveying marsh gas. The fourth pipeline is connected with an additional air source device for conveying the additional gases. The air compressor is connected between the heat exchanger and the fermentation tank. An INDEPENDENT CLAIM is included for producing marsh gas using the dry anaerobic fermentation system.