Abstract: A method of forming a colored pattern on the surface of aluminum or aluminum alloy comprising the steps of subjecting the surface to a first electrolytic treatment to form a background of anodic oxide film, and placing a pattern-forming electrode against the surface in adjacent but spaced apart relation. The surface is then subjected to a second electrolytic treatment to electrochemically impress the pattern onto the background by applying a voltage between the surface and the pattern-forming electrode in an electrolytic bath containing a metallic salt. The pattern-forming electrode is removed from the surface, and the surface having the background and the pattern is subjected to a third electrolytic treatment in an electrolytic bath containing a metallic salt to develop difference in color tones and intensities between the background and the pattern.