The invention discloses a process for covering an aluminum base composite material layer on a complicated surface aluminum diamond product surface. Firstly, nonmetal powder and a bonding agent are mixed as a pasty spraying material; then, a demolding agent is sprayed on the inner side of a molding cavity of a molding mold for die casting of an aluminum diamond composite material product; after thedemolding agent is dried, a layer of isolating agent is sprayed on the demolding agent; after the isolating agent is dried, a layer of paste mixed by the nonmetal powder and the bonding agent is sprayed on the isolating agent; after the paste is dried and cured, the product molding mold is assembled; diamond powder is filled in a cavity, on the inner side sprayed with the paste, in the molding mold; the diamond powder is vibrated and compacted to tightly bond with the dried paste layer; and in the die casting and aluminum permeating process, die-cast aluminum is permeated in the paste layer of the nonmetal powder, and is firmly connected with the aluminum diamond composite material to realize coverage of an aluminum-nonmetal composite material layer, capable of performing machining and plating, on the surface of a cooling device.