The invention discloses a method for generating 
methane in a 
methane generation device with a bent super-long 
fermentation path. The method includes the steps: pouring 
fermentation raw materials from a feeding 
pipe and fermenting the raw materials in a 
fermentation pipeline to generate the 
methane; using the methane stored in an optional fermentation area. The methane is respectively gathered in fermentation areas formed among the feeding / discharging 
pipe and adjacent gas baffle plates or between the adjacent gas baffle plates, occupies space in the fermentation areas, squeezes 
biogas slurry in 
convection and flows towards the feeding 
pipe, the discharging pipe and a 
bacteria distribution device, and the 
biogas slurry in the fermentation pipeline unidirectionally flows into a 
water pressure space through a drain hole of the discharging pipe and flows into the 
water pressure space through a drain pipe of the 
bacteria distribution device along with rise of the liquid level of the 
biogas slurry in the feeding pipe, the discharging pipe and the 
bacteria distribution device. The pressure of the methane stored in the optional fermentation area is reduced, the biogas slurry in an adjacent fermentation area flows towards the optional fermentation area, and the biogas slurry stored in the 
water pressure space unidirectionally flows back into the feeding pipe through a drain hole of the feeding pipe and flows back into the fermentation pipeline through the drain pipe of the bacteria distribution device to supplement reduced methane space, so that circulating flow of the biogas slurry is finished.