The invention discloses a process for resisting ferrous metal corrosion of a zinc nickel diffusion layer. The process comprises the steps of alkaline degreasing, shot blasting, heating diffusion layer, water washing dust removal and colorful closing according to the requirement of a customer, wherein in the heating diffusion layer step, the zinc nickel diffusion layer and a metal matrix are put in a sealed metallic container and heated; the zinc nickel diffusion layer is prepared by evenly mixing the following powders in mass proportion: 20 to 30 percent of Zn powder, 0.5 to 1.4 percent of Ni powder, 3 to 12 percent of Al powder, 2 to 6 percent of rare earth, 1 to 4 percent of NH4Cl ammonium chloride, the balance being Al2O3 powder. The diffusion layer has the advantages of high rigidity, good wear resistance, unchangeableness of original mechanical performances of products, high adhesion strength, bumping and rolling resistance, good solderability, moisture and heat resistance and acid and alkali resistance; the diffusion layer has uniform thickness and compactness, and appearances of finished products have good uniformity; and no three-waste emission occurs during the course of processing, so the process belongs to the clean production process and is environment-friendly.