The invention discloses a composite artificial board produced by using a scraped car roof and a preparation method thereof, and relates to the technical field of the artificial board. The composite artificial board comprises at least two layers of substrate layers; a sound-insulating and heat-insulating layer is installed between the substrate layers; the sound-insulating and heat-insulating layer is the scraped car roof board layer; and a glue layer is installed between the substrate layer and the sound-insulating and heat-insulating layer. The preparation method comprises the steps: coating the glue on one or two faces of the wood board, overlapping with the scraped car roof, forming by pressing, and obtaining the composite artificial board in the certain standard. The strength of the artificial board manufactured by the preparation method is similar to the strength of the common artificial board in the market, and because the car roof has the polyurethane foam with good sound-insulating and heat-insulating performance, the sound-insulating and heat-insulating effect is better than that of general artificial board, the density is smaller than that of the normal artificial board, and more important is that the difficultly-processed scraped car roof in the auto industry can be recycled, the process is simple, and the production efficiency is high.