Specially designed for large-scale continuous production of polyurethane sandwich panels used in building exterior wall insulation, cold storage walls, clean workshops and prefabricated buildings. It is suitable for composite of various face materials such as color steel, aluminum foil and paper honeycomb, meeting the core needs of uniform panel density, thermal insulation, flame retardancy, compression resistance and standard size, and adapting to large-scale automatic production lines in the building materials industry.