NOVELTY - The large-particle straw marsh gas fermentation device comprises a fermentation tank and a liquid storage unit, where the fermentation tank is provided with a vertical tank body. A top part of the tank body is provided with a feeding pipe and a marsh gas pipe. The marsh gas pipe is provided with a first valve. A bottom part of the tank body is provided with second valve. The feeding pipe is provided with a gravity feeder. The top part of the tank body is provided with a reflowing pipe. The reflowing pipe is connected with the liquid storage unit through circulating pump.    USE - Used as large-particle straw marsh gas fermentation device.    ADVANTAGE - The device is smooth to feed and discharge, has high input-output ratio, and consumes less energy.    DETAILED DESCRIPTION - The large-particle straw marsh gas fermentation device comprises a fermentation tank and a liquid storage unit, where the fermentation tank is provided with a vertical tank body. A top part of the tank body is provided with a feeding pipe and a marsh gas pipe. The marsh gas pipe is provided with a first valve. A bottom part of the tank body is provided with second valve. The feeding pipe is provided with a gravity feeder. The top part of the tank body is provided with a reflowing pipe. The reflowing pipe is connected with the liquid storage unit through circulating pump. The upper part of the tank body is provided with an overflow pipe and/or a point of the liquid level indicating component. The overflow pipe is higher than the feeding pipe. The marsh gas pipe is provided with an inlet. The tank body is equipped with a circular table slag-stopping ring plate. The slag-stopping ring plate is connected with the feeding pipe. The slag-stopping ring plate is connected with the upper end of the inner wall of the tank body. A lower end of the tank body is equipped with a liquid slag separating plate. The liquid slag separating plate is provided with holes. The liquid slag separating plate is provided with a slag discharging port, which is connected with the fermentation tank. The fermentation tank is provided with a discharging pipe with a third valve. A drain pipe is connected with the liquid storage unit. The liquid storage unit is provided with a sieve plate and/or a slag frame. The inner wall of the tank body is equipped with a connecting pipe, which is arranged higher than the overflow pipe. The connecting pipe is located in the liquid slag separating plate. The liquid storage unit is liquid storage tank. The overflow pipe outlet is connected with the liquid storage unit. The gravity feeder is connected with the feeding pipe. The gravity feeder is provided with a locking device on the feeding pipe. An upper part of the gravity feeder is connected to the fermentation tank through a feeding pipe. Angle between the slag baffle ring plate and the liquid slag separating plate is more than 15-30 degrees C.