The invention relates to a tarnish-resistant method of gold and platinum, the procedure of the invention includes oil removal, water scrubbing with ultrasonic, polishing, activation, acid cleaning, and chemical passivation, cleaning with hot water and dehydration and drying. All procedures are cleaned with distilled water for more than 20 seconds. The method is characterized in that the tarnish-resistant process on the surface of gold, platinum and the alloy of gold and platinum is completed in chemical passivation liquid; when the gold, the platinum and the alloy of gold and platinum are passivated, the surface is covered with giant molecule of organic substance; as the passivation liquid has no chromate content, the pollution to the environment is reduced; the surface metallic luster and the appearance of the gold and platinum products has no change after the process. The invention has an easy process procedure and convenient operation, thus having great industrial application value.