The invention discloses a method and a device for comprehensively processing pig manure in a large-scale pig farm. The method for comprehensively processing pig dung in the large-scale pig farm comprises the following steps: S1, the pig dung in pig houses is collected by a mechanical dung scraping facility, and is transported into a dung collecting tank; S2, the pig dung in the dung collecting tank is added into a fermentation tower by a screw conveyor, undergoes anaerobic dry fermentation to produce biogas, and then undergoes aerobic composting; S3, the biogas generated in the anaerobic dryfermentation process is introduced into and stored in a gas storage cabinet, odorous gas generated during the aerobic composting is introduced into a biological filter and is processed, the above produced organic fertilizer is transported to a curing workshop and is cured, and generated biogas slurry and leachate enter an anaerobic fermentation reactor by a pump, and are used to produce biogas; and S4, the biogas obtained in step S2 and step S3 is purified, and then used, the produced organic fertilizer is returned to the field, and the generated biogas slurry is used for irrigating crops after being discharged into an oxidation pond and processed. The method and the device have the advantage of good processing effect, simple process conditions, no secondary pollution and high economic benefits.