NOVELTY - Producing biogas by large multi-level interaction biogas fermentation device, comprises pouring fermentation raw material into multi fermentation tank inlet, collecting the fermentation biogas in upper portion of the gas plate inside fermentation chamber, storing biogas within gas storage plate, increasing gas pressure, squeezing gas storage plate, eluting biogas, raising level of fermentation tank slurry, discharging biogas slurry into slow fermentation efficiency of fermentation tank, removing fermentation tank blocking, clearing the pipeline, passing biogas slurry and discharging.    USE - The method is useful for producing biogas by large multi-level interaction biogas fermentation device (claimed).    DETAILED DESCRIPTION - Producing biogas by large multi-level interaction biogas fermentation device, comprises pouring fermentation raw material into multi fermentation tank inlet which is connected between the water pressure, collecting the fermentation biogas in upper portion of the gas plate inside fermentation chamber, fixing the gas storage plate above the fermentation chamber by supporting device, moving side of the rod by pulling the lever, swinging gas plate and fermentation tank, storing biogas within the gas storage plate, increasing gas pressure, squeezing gas storage plate, eluting biogas, raising level of fermentation tank slurry, flowing into drainage pipe which is connected between fermentation tank and water pressure, where the multiple fermentation tank surrounded by water pressure, discharging biogas slurry from high fermentation efficiency of the fermentation tank into slow fermentation efficiency of fermentation tank, removing fermentation tank blocking by pulling the lever, driving the bottom rod of crossbar swing in fermentation tank, moving the lever of vertical rod on sides of the gas storage plate and fermentation tank, clearing the pipeline , storing biogas within gas storage plate, reducing biogas slurry level in fermentation tank, passing biogas slurry from other fermentation tank through water pressure and flowing into fermentation pool.