TECHNOLOGY FOCUS - BIOTECHNOLOGY - Preferred Method: In methane production, from the step (a) to the step (d), multiple anaerobic tanks are arranged; the engineer running is designed to be a circulating sequencing manner so as to guarantee that at least one anaerobic tank runs and produces methane in each engineer running period; and after running of one anaerobic tank is finished and the material is discharged, the raw material amount is controlled for feeding material, stacking, fermenting and producing methane according to the pre-treatment and preset fermenting time. In the step (a), the material and the inoculum or conditioner are mixed in layers; the stacking time is controlled for 2-15 days; the moisture of the mixed material is controlled in a range of 50%-70%; and the content of the total solid is controlled in a range of 30%-50%. The fermenting temperature for stacking the material is over 42 degrees C; and the time is 2-3 days. The C/N ratio of the integral material is controlled in a range of 6-60 after the step (a) of adding inoculum or conditioner and the step of adding biogas slurry. The C/N ratio of the integral material is further controlled in a range of 25-30. In the step (c), the biogas slurry and the residual sludge are discharged via a reflowing pump so as to adjust the volume loading of the anaerobic tank; the step of biogas slurry reflowing or adding water is performed through an automatic spray device; and the step of stirring at regular intervals is automatically performed via the reflowing pump. In the step (a), the raw material is at least one of the dry or fresh crop straws, excrement of animals, biological waste material and blue-green algae; and the inoculum or conditioner is at least one of excrement of animals, biogas slurry, sludge in methane ponds, sludge in sewage plants and microbial inoculum. In the step (c), during the fermenting period, the material that is pre-treated or not pre-treated is manually or mechanically added so as to increase the yield of methane; and the amount of the added material must guarantee the content of the total solid in the anaerobic tank in a range of 10%-25%.