The invention discloses a clean rare-earth salt passive film, mainly used for post treatment procedure of galvanizing or zinc-iron alloy of steel parts, belonging to the technical field of metal material surface treatment. A bright dipping solution composed of 2-5ml of HNO3 and H2O as well as a passivation solution composed of 15-30g/L of cerous nitrate or cerium chloride, 2-5g/L of K2S2O8, 2-6g/L of Na2SiO3, 2-6g/L of H2BO3, 5-20ml/L of H2O2, 5-15ml/L of HCl and the balance being H2O are prepared, diluted HCl or NaOH solution is used for adjusting the pH value to 1.8-2.8, then the steel parts of the galvanizing or zinc-iron alloy is taken out, washed and then placed in the bright dipping solution for 3-10 seconds, washed by running water and then placed in the passivation solution for passivation of 30-90 seconds at room temperature, and taken out, washed by running water and dried by an air blower. The corrosion resistance of the steel parts of the galvanizing or zinc-iron alloy processed by the passivation technique is remarkably improved, and the passivation technique has the advantages of toxic substance-free, high stability and reliability, excellent product performance, belongs to clean and environment-friendly, economic and practical chromium-free passivation technique and has significant social meaning and application value.