Electrophoretic coating has a different effect from general inorganic electrolyte electric fields, and it is also different from electroplating, mainly manifested in the conductivity of electrodeposited materials. During electroplating, the conductivity between the electrodes does not change after electrodeposition, while organic coatings, due to their insulation properties, undergo significant changes in electrode resistance during electrodeposition of water-based coatings. At the beginning of electrodeposition, point like deposits appear and gradually connect into flakes. As electrodeposition continues, some parts of the electrodeposit are insulated, and when the resistance rises to a certain extent, electrodeposition hardly continues at point I. The electric field distribution gradually moves towards 1, and the electrodeposition gradually moves towards the uncoated part with the formation of the paint film until the surface is fully coated.