Electronic products may come into contact with moisture during use. If they are not waterproof, internal parts or circuit boards will be eroded by moisture and their service life will not be long. In addition, small impurities will also enter into electronic products, affecting their normal operation. Waterproof tester is a new type of high precision nondestructive testing equipment. It mainly uses compressed air as a medium to apply a certain pressure to the inner cavity or outer surface of the product to be tested, and then uses a high-sensitivity sensor to detect the pressure change, thus determining the tightness of the product to be tested. Because it uses compressed air as the medium to cause no secondary pollution to the product, and the detection speed and accuracy are also better than that of water detection (air molecules are smaller than water molecules, and the leakage speed is fast), it can be implemented on a large scale in the production line.