The invention designs a cast rolling composite production device and method of a metal composite plate. The cast rolling composite production method provided by the invention comprises the steps that a base metal to be composited enters a molten pool of a thin belt continuous casting machine from top to bottom through a base metal uncoiler and a guide roller, wherein the molten pool is internally provided with a to-be-composited layer metal liquid, and as the temperature of the base metal is lower than that of the to-be-composited layer metal liquid, the liquid can crystallize on the surface of the base metal, which is equivalent to a hot dipping process; meanwhile, a crystallizing roller is cooled through water, the metal liquid also crystallizes on a contact region of the crystallizing roller and the metal liquid, and when the base metal reaches an occlusion hole of the crystallizing roller, the crystallizing roller can press a crystallized metal thin layer on a roller surface on a crystallizing layer of the base metal, thereby forming a composite plate material; when the composite plate material leaves the occlusion hole to enter a secondary cooling region, the composite plate is further cooled through a smooth roller and is rolled through a rolling mill, and finally, the composite plate is reeled up so as to form a roll. According to the invention, the production processes are simplified, the production cycle is shortened, the equipment investment is correspondingly reduced, and the product cost is obviously reduced.