The invention discloses the surface protection technology for copper, aluminum alloy, steel core and nickel plated coin and seal. The feature is that: hanging the coin or seal, removing oil by ultrasonic, the first pulverization spraying washing, rinsing, cathode electrophoresis, the second pulverization spraying washing, the first counter-flow wash, the second counter-flow wash, drying by hot air, light fixed drying and taking down the product. The invention uses the method of cleaning the surface of metal and uniform distributing the film of amino third diluted acid colophony formed by cathode electrophoresis and light fixing on the surface of the metal. Thus, the surface of the metal would be effectively protected.