NOVELTY - Integrated solid-material two-phase methane fermentation reactor comprises reactor structure, stirrer, heating coil, double-membrane methane storage device, acidifying area feeding pipe, methane-producing area feeding pipe and discharging pipe, where the reactor structure is in an inner-outer double-layer structure, outer layer is a hydrolyzing and acidifying area, and inner layer is a methane-producing area.    USE - As integrated solid-material two-phase methane fermentation reactor.    ADVANTAGE - The integrated solid-material two-phase methane fermentation reactor improves heat preservation efficiency, increases yield of the methane, and has high operation load, and is rapid, as compared to existing fermentation reactor.    DETAILED DESCRIPTION - Integrated solid-material two-phase methane fermentation reactor comprises reactor structure, stirrer, heating coil, double-membrane methane storage device, acidifying area feeding pipe, methane-producing area feeding pipe and discharging pipe, where the reactor structure is in an inner-outer double-layer structure, outer layer is a hydrolyzing and acidifying area, and inner layer is a methane-producing area. The material enters the acidifying area through the hydrolyzing and acidifying area feeding pipe along the tangential direction of the reactor structure and overflows into the methane-producing area from the top of the acidifying area. The fermented material overflows out of the reactor body from the top of the methane-producing area. An INDEPENDENT CLAIM is included for method for preparing methane using the above-mentioned integrated solid-material two-phase methane fermentation reactor, which involves continuously feeding the material in the hydrolyzing and acidifying area for 2 days at 25-35 degrees C and pH 5.5-6 (stirring for 5-10 revolutions per minute (rpm)) using the hydrolyzing and acidifying area feeding pipe along the tangential direction of the reactor structure, converting the material to organic matter using anaerobic microorganism, overflowing the acidified material into the methane-producing area from the top of the acidifying area, converting the material to methane, where methyl hydride and marsh gas are in the main portion of methane-producing area, where the material stays in the main portion of methane-producing area for 15-20 days at 35-55 degrees C and pH 6-8 (stirring for 5-10 rpm), and generated methane is stored at double-membrane methane storage device (generated methane is conveyed through the pipeline for further treatment).