NOVELTY - The high-concentration straw marsh gas fermentation device comprises a fermentation tank, and liquid storage unit. The fermentation tank is a vertical tank body. A top part of the tank body is provided with a feeding pipe and a marsh gas pipe. A bottom part of the tank body is provided with a slag discharging port. The feeding pipe is provided with a gravity pusher. The top of the tank body is further provided with a reflowing pipe, an overflow pipe and a return pipe through a circulating pump. The circulating pump is connected with the liquid storage unit.    USE - Used as a high-concentration straw marsh gas fermentation device.    ADVANTAGE - The high-concentration straw marsh gas fermentation device has low energy consumption and reduced input/output ratio.    DETAILED DESCRIPTION - The high-concentration straw marsh gas fermentation device comprises a fermentation tank, and liquid storage unit. The fermentation tank is a vertical tank body. A top part of the tank body is provided with a feeding pipe and a marsh gas pipe. A bottom part of the tank body is provided with a slag discharging port. The feeding pipe is provided with a gravity pusher. The top of the tank body is further provided with a reflowing pipe, an overflow pipe and a return pipe through a circulating pump. The circulating pump is connected with the liquid storage unit. The tank body is installed on an upper part of a slag ring plate. The slag ring plate is connected with the feeding pipe. The tank body has an innerwall that are provided with an annular open pore. The bottom end of the tank body is equipped with a slag separating plate. The slag separating plate is set with holes. The inner wall of the tank body, the slag separating plate and the slag discharging port are connected with the fermentation tank through a discharging pipe. The liquid storage unit is connected with a drain pipe. The inner wall of the tank body is equipped with a connecting pipe. The connecting pipe is located in the slag separating plate. The overflow pipe is connected with the liquid storage unit. The gravity pusher is connected with the feeding pipe, and is provided with a locking device placed on the feeding pipe. The slag ring plate has an inclination angle of greater than 30, preferably 15 degrees C.