For the repair and repair method of electro-coating, the reasonable thickness of repair is within 0.12mm, which can basically meet the maintenance requirements of the even-wear Hydraulic Valve, and further processing is still required after the repair. In terms of electro-coating repair and maintenance, the more common process is chemical composite electro-coating. This process is developed based on mature electro-coating process. Its advantages are convenient operation method, relatively simple equipment, and comparative cost. Low, and easier to control the reaction. In the hydraulic valve maintenance process, the process can be used to precipitate a composite coating with more components on the surface of the valve hole or valve core, and the coating can be firmly combined with the parent metal, and its mechanical strength is relatively high , The thermal conductivity is also relatively good, at the same time its thermal expansion coefficient is relatively low, and the friction coefficient is relatively low, and its self-repairing ability is also relatively strong, so the use of this method can get a relatively ideal effect in the maintenance of Hydraulic Valve.