Electrophoretic coating (electro-coating) is a coating method that utilizes an applied electric field to make particles such as pigments and resins suspended in an electrophoretic solution migrate directionally and be deposited on the surface of one of the electrodes of the substrate. Electrophoretic coating is a special coating film formation method developed in the past 30 years, which is the most practical construction process for water-based coatings. It is characterized by water solubility, non-toxicity, easy automation control, etc., and has been widely used in automobile, building materials, hardware, home appliances and other industries.