Process for electroplating chromium by plastic

A method for electroplating chromium on plastics which comprises the steps of: plating copper tin alloy on a conductive plastic substrate, primary washing with water, plating palladium, secondary washing with the water, and plating chromium, wherein the primary washing with the water and the secondary washing with the water comprise at least once water-washing operation, and the temperature of at least once water-washing operation is not lower than 30DEG C. The method for electroplating the chromium on the plastics can effectively increase the binding power of a plating layer and can effectively prevent bubbling and peeling phenomena between a copper tin coating, a palladium coating and a trivalent chromium coating, the method also can effectively reduce the pinhole phenomenon on the surface of the coating, and the product percent of pass can be highly improved to 95 percent.