Composite paper is laminated with paper, paperboard and other plastics, aluminum foil, cloth, etc. with an adhesive to obtain a composite processed paper. Composite processing paper can not only improve the appearance and strength of paper and paperboard, but also improve the performance of waterproof, moisture-proof, oil-proof, air-tight and fragrant, etc. At the same time, it will also obtain heat-sealing, light-blocking and heat-resistance. The methods for producing composite paper include wet, dry, hot-melt and extrusion composite processes.