Spark test is a non-destructive testing method widely used to detect pinholes, cracks, porosity and other defects in non-conductive coatings, linings and insulation layers on metal substrates. By applying a high-frequency high-voltage electric spark between the probe and the workpiece, defects will cause spark discharge and give an alarm, realizing rapid and accurate inspection. This test is safe, efficient and intuitive, suitable for quality inspection of glass lining, rubber lining, plastic coating, enamel and other anti-corrosion equipment. It is widely applied in chemical, pharmaceutical, food and pressure vessel industries to ensure the integrity and anti-corrosion performance of equipment surface layers, reduce potential leakage risks and improve product safety and service life.