NOVELTY - Methane generation system comprises a feeding pipe, a discharging pipe and a U-shaped fermentation pipeline. The U-shaped fermentation pipeline is horizontally placed. The feeding pipe and the discharging pipe are vertically connected with two end sides of the fermentation pipeline. A water pressure space is formed on the U-shaped fermentation pipeline, a feeding pipe drain hole is formed in the joint of the water pressure space and the feeding pipe, and a discharging pipe drain hole is formed in the joint of the water pressure space and the discharging pipe.    USE - The system is useful for hydraulically and pneumatically promoting uniform bacteria distribution (claimed).    ADVANTAGE - The system: utilizes U-shaped channel-type fermentation device; has long fermentation path; sufficiently flows the biogas slurry in the system by control of water pressure difference and one-way valves; can drive bacteria to be uniformly distributed; prevents crusting; and has gas generating rate.    DETAILED DESCRIPTION - Methane generation system comprises a feeding pipe, a discharging pipe and a U-shaped fermentation pipeline. The U-shaped fermentation pipeline is horizontally placed. The feeding pipe and the discharging pipe are vertically connected with two end sides of the fermentation pipeline. A water pressure space is formed on the U-shaped fermentation pipeline, a feeding pipe drain hole is formed in the joint of the water pressure space and the feeding pipe, a discharging pipe drain hole is formed in the joint of the water pressure space and the discharging pipe, a feeding pipe gas baffle plate is arranged at the joint of the U-shaped fermentation pipeline and the feeding pipe, a discharging pipe gas baffle plate is arranged at the joint of the U-shaped fermentation pipeline and the discharging pipe, at least one gas baffle plate is arranged between the discharging pipe gas baffle plate and the feeding pipe gas baffle plate, a fermentation area is formed among the feeding/discharging pipe and the adjacent gas baffle plates or between the adjacent gas baffle plates, an independent gas collecting pipe is arranged at the top of each fermentation area, the top of each fermentation area is connected with the independent gas collecting pipe, and a valve is arranged on each gas collecting pipe. The water pressure space is also connected to a bacteria distribution device. The bacteria distribution device comprises a drain pipe, a bacteria distribution pipeline and a bacteria distribution hole. One end side of the drain pipe of the bacteria distribution device is connected to the water pressure space, and the other end is connected to the bacteria distribution pipeline, which is horizontally placed. Each fermentation area of the fermentation pipeline is connected to the drain pipe of the bacteria distribution device for promoting the slurry flow within the each fermentation area. The bacteria distribution pipeline is provided with multiple bacteria distribution holes, which passes vertically. The bacteria distribution pipeline is fixed to the U-shaped fermentation pipeline and extends into the fermentation areas of the fermentation pipeline. The feeding pipe drain hole is provided with a unidirectional valve for controlling biogas slurry unidirectional inflow within the water pressure space of the feeding pipe. The discharging pipe drain hole is provided with the unidirectional valve for controlling biogas slurry unidirectional inflow within the water pressure space of the discharge pipe. The drain hole of the bacteria distribution device is provided with the unidirectional valve for controlling biogas slurry unidirectional flow into the fermentation pipeline.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic representation of the methane generation system for hydraulically and pneumatically promoting uniform bacteria distribution.