The resin contained in the cathodic electrophoretic coating has basic groups,which form a salt after acid neutralization and dissolve in water. After the direct current is applied, the acid radical negative ions move to the anode and the resin ions and the pigment particles wrapped in it move to the cathode with positive charges and are deposited on the cathode. This is the basic principle of electrophoretic coating (commonly known as paint coating) Electrophoresis coating is a very complex electrochemical reaction. It is generally believed that at least four effects of electrophoresis, electrodeposition,electrolysis, and electroosmosis occur simultaneously. It is widely used in automobiles, high-speed rail and other industries.