NOVELTY - Methane is produced by crushing organic garbage and placing into comprehensive pre-processing pool; mixing the crushed organic garbage with sludge from urban sewage processing factories and animal excrements; diluting the mixed materials into suspension solution containing 8-12% solids by the sewage or pure water in a farm; and causing the pre-processed material satisfying a material feeding requirement of an anaerobic reactor to enter an anaerobic reactor via a material feeding pump and a pipeline to ferment.    USE - The method is used for producing methane. Methanol produced by fermentation can be directly used as fuel gases for warming or cooking in processing factories and surrounding farmers after being purified. The residual part is used for generating electricity for self-use or surfing on internet by a methanol generator group. The methanol liquids and methanol residues are used as organic fertilizers and returned to farm lands. (all claimed)    ADVANTAGE - The method reduces unit investments and running maintenance cost over 10%. Compared with methanol produced quantity by separate fermentation of sludge or animal excrements, the methanol produced quantity in the method is enhanced.    DETAILED DESCRIPTION - Producing methane comprises crushing organic garbage and placing into comprehensive pre-processing pool; mixing the crushed organic garbage with sludge from urban sewage processing factories and animal excrements; diluting the mixed materials into suspension solution containing 8-12% solids by the sewage or pure water in a farm; and causing the pre-processed material satisfying a material feeding requirement of an anaerobic reactor to enter an anaerobic reactor via a material feeding pump and a pipeline to ferment. The anaerobic digestion sludge in an anaerobic reactor of an excrement management methanol engineering of animal feeding factories or a sludge anaerobic reactor of urban sewage processing factories is used as inoculating sludge (15-30 vol.%). A mass ratio of the organic garbage, sludge from the urban sewage processing factories and animal excrements is 1:1-3:1-3. At an actual running, the mass ratio is adjusted according to garbage collection, sludge production and excrement production, while the percentage of organic garbage should be controlled within a mass ratio of less than or equal to 1/3 to prevent acidification. The material feeding method is intermittent. Each feeding lasts for 15-30 minutes. The materials are fed for 1-8 times every day. Every material fed amount is 1/25-1/15 of the designed volume of the reactor. The material discharged amount is equal to the material fed amount. The material amount in the reactor is 80-90% of the designed volume of the reactor. Water power of the materials in the reactor stays for 15-20 days. A pH of the materials in the reactor is at 6.8-7.2. Reaction is controlled at 33-37 degrees C. After the running is stable, the volume gas production rate of the reaction is over 1 m3/m3-day. The methanol gas contains 55-70% methanol and 30-45% carbon dioxide.