NOVELTY - Device comprises e.g. a livestock and poultry manure processing unit, a mixing unit and an anaerobic fermentation reactor at least comprises a shell (18), a stirring part, a containing part, a detecting unit and a control unit. The control unit is used for controlling a hydraulic pump to pump livestock and poultry manure and wastewater in an expected value according to a production period. The livestock and poultry manure is mixed with wastewater in a preset ratio to form mixed feed. The control unit is also used for controlling a fermentation temperature to be constant at 35 degrees C temperature.    USE - The device is useful for treating farm waste (claimed).    DETAILED DESCRIPTION - Device comprises a livestock and poultry manure processing unit for treating livestock and poultry manure, which has an inclined funnel-shape at the center position, a wastewater separating unit located in a wastewater processing unit comprises floating oil, which can separated from the wastewater, a filter assembly of foam suspended solid and solid impurities, a mixing unit comprises a mixing member for mixing the livestock and poultry manure and wastewater according to predetermined mixing ratio to obtain mixed feed, where the solid concentration of the mixed feed is 6-11%, an anaerobic fermentation reactor (17) at least comprising a shell (18), a stirring part, a containing part, a detecting unit and a control unit. The stirring part is located in the shell and comprises at least one of a stirring shaft and a stirring blade of stirrer. The stirring blade is located in the stirring shaft and uniformly distributed, which are fixedly set. A stirring area of the adjacent stirring blade is partially overlapped. A control unit is used for controlling at least one stirrer during alternative operation. Microbial inoculum inlet is connected to the containing part comprises a cylindrical inner wall. The cylindrical inner wall is surrounded by an outer wall and a bottom plate of the outer wall is connected to the cylindrical inner wall. An annular space between the inner wall and outer wall is filled with folded soft biological filler and the annular space is formed with a bio-film. The inner wall and the outer wall are set with a through hole, and comprises a processor, a storage device and a communication interface of control unit connected to the livestock and poultry manure processing unit, a mixing unit, a feeding part (20) and a discharging part (21) of hydraulic pump, a brake and a stirring motor. The upper part of the shell is set with a temperature control device (19) and a detecting unit. The control unit is used for controlling the hydraulic pump to pump livestock and poultry manure and wastewater in an expected value according to a production period. The control unit is also used for controlling a fermentation temperature to be constant at 35 degrees C temperature and the pH value to be 6.8-7.4, and a signal is sent to start the stirring motor to drive the stirrer to stir the mixed raw materials in the anaerobic fermentation reactor, and slaking reaction is carried out, hence methane is produced and residue is discharged. An INDEPENDENT CLAIM is also included for treating the farm waste, comprising providing the device for treating farm waste, then treating the livestock and poultry manure and wastewater by the processing unit, mixing the processed livestock and poultry manure and wastewater by the mixing unit to obtain the mixed feed, controlling the fermentation temperature at constant temperature of 35 degrees C and pH between 6.8-7.4, recycling the mixed feed into the anaerobic fermentation reactor and carrying out slaking reaction to produce methane and material residue, and adjusting the gas production rate using the control unit according to the reaction conditions.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic representation of the device for treating farm waste.    Anaerobic fermentation reactor (17)    Shell (18)    Temperature control device (19)    Feeding part (20)    Discharging part (21)