Passivation technology of phosphating film is widely used in North America and European countries. Passivation technology is based on the characteristics of phosphating film itself. Phosphating film is thin, it is generally in 1-4g/m2, the maximum is not more than 10g/m2, its free pore area is large, and the corrosion resistance of the membrane itself is limited. Some even quickly produce yellow rust in the drying process. After phosphating, a passivation treatment can be used to further oxidize the exposed metal in the pores of the phosphating membrane, or to generate the passivation layer, which can fill and oxidize the phosphating film, and make the phosphating film stable in the atmosphere.