The invention relates to the field of methane production equipment, in particular to a single pool multi-bed methane fermentation device. The single pool multi-bed methane fermentation device comprises a casing and a support leg, wherein the top and the bottom of the casing are respectively provided with a feeding opening and a slag discharging opening; a material distribution fermentation unit is arranged in the casing in a laminated way, and comprises a flow division device, an upper dispersion bacterium fixing bed, a lower polymerization bacterium fixing bed and material distribution exhaust pipes; the flow division device is fixedly arranged in the core part of the casing; the upper dispersion bacterium fixing bed in a conical surface shape is arranged under the flow division device; the lower polymerization bacterium fixing bed in a reverse conical surface shape is fixedly arranged under the upper dispersion bacterium fixing bed; material distribution exhaust pipes are uniformly distributed and arranged at the circumference on the outer conical surface of the upper dispersion bacterium fixing bed in a staggered way; the material distribution exhaust pipes are uniformly distributed and arranged down the circumference of the inner conical surface of the lower polymerization bacterium fixing bed in the staggered manner; an overflow pipe is vertically arranged on a pipeline of the slag discharging opening. The single pool multi-bed methane fermentation device provided by the invention has the advantages that the building cost is lower; the gas producing rate and the fermentation concentration are high; the fermentation raw material utilization rate is greatly improved.