The invention relates to a production process of a metal hard foam polyurethane composite decorative sheet. The production process comprises the following steps of step 1, prefabricating a coated metal coil; step 2, producing a basic die with a groove body after molding the prefabricated coated metal coil through a rolling bending machine; and step 3, placing a foaming material into the groove body of the basic die to be foamed to produce hard foam polyurethane, then covering a metal film on the surface of the hard foam polyurethane through the guide, sending the metal film into an insulation box to be thermally insulated after shaping the metal film, and producing the metal hard foal polyurethane composite decorative sheet. After the metal hard foam polyurethane composite decorative sheet is installed, a seamless fireproof, damp-proof, heat-preserving and sound-proof wall which is easy to scrub is formed.