The invention belongs to the field of resource utilization of stock raising waste, and discloses an integrated biogas production and composting device and method for a pig manure percolation bed. Themethod comprises the following steps that pig manure is placed into a percolation bed biogas production unit, and a biogas liquid is added for soaking; a percolation liquid treated by a water soakingmanure percolation bed is discharged into a CSTR fermentation biogas production unit, and the biogas is produced through anaerobic digestion of methane bacteria; a supernatant of the CSTR fermentationbiogas production unit as process water flows back into a water soaking manure percolation bed unit; a liquid between the water soaking manure percolation bed unit and the CSTR fermentation biogas production unit is circulated back and forth; percolation residues of the water soaking manure percolation bed unit are taken out, and through bio-drying, the product can be used as a base fertilizer. The integrated biogas production and composting device and method for the pig manure percolation bed have the advantages that the problem of the dung disposal and biogas liquid discharge of pig farms is effectively solved, the treatment efficiency is high, the technological conditions are simple, the secondary pollution is less, the economic benefits are high, and the device and method are suitablefor dung and biogas liquid treatment of the pig farms.