Pre-painted steel sheet production line:color coating steel sheet is composed of cold rolled steel sheet and galvanized steel sheet as substrate. Pre-painted steel sheet production line: surface advanced degreasing, cleaning and chemical conversion treatment), coating is painted by continuous method (roller coating method), and products are produced by baking and cooling. Coated steel plate is light and artistic with good anti-corrosion performance. It also can be directly processed, a novel raw material is provided for construction, shipbuilding, automobile manufacturing, furniture industry, electrical industry, etc., which has excellent effect in replacing wood by steel, efficient construction, energy conservation, pollution prevention, etc.