Abstract: When there is cooling water in the tube side of the water cooler, heat exchange tube sections adjacent tube box often experience corrosion and leakage. By arranging sacrificial anodes in the tube box, corrosion on the inner wall of the tube box can be effectively alleviated, but whether it can provide protection for adjacent heat exchange tubes remains to be studied. By using numerical simulation method to design sacrificial anodes for a certain type of water cooler tube box, 6 anodes were added and a coating was added to the inner wall of the tube box. The inner wall area of the tube box could be well protected while providing protection for adjacent heat exchange tubes. Although the protection range was only 0.75 meters, it had already covered the parts of the heat exchange tubes that were prone to corrosion and leakage. In addition, the completeness of the coating determined the protection range of the cathodic protection of the tube box for adjacent heat exchange tubes.