In order to get colourful passivation film with excellent corrosion resistance, the Cr3+ iridescent passivation technology with fine corrosion resistance at low temperature on electrogalvanizing was studied. The corrosion resistance dependences on complexing agent, metal salt, pH, passivation temperature, and dip time were discussed, and the best technological procedure was obtained. The passivation film we got is uniform, shinning with iridescence. And its corrosion resistance is excellent. Compared with electrogalvanizing, the surface of passivation film is smooth and uneven which is in favor of improving the corrosion resistance of passivation film.