Abstract: After six months of storage, white spots were found on some areas of the surface of a hot-dip galvanized sheet. The causes of surface white spots on hot-dip galvanized sheets were analyzed using macroscopic observation, chemical composition analysis, scanning electron microscopy and energy spectrum analysis, X-ray diffraction analysis, metallographic examination. The results show that galvanized sheets were stored in a high-temperature, high humidity, and high salt marine atmospheric environment. The humid air condensed into a liquid film on some areas of the sheet surface, and Cl^－ adsorbed on the metal surface, resulting in an increase in the conductivity of the medium and a decrease in the resistance of the surface rust layer, and led to corrosion of the galvanized layer, generated ZnO corrosion products, and ultimately formed white spots on the sheet surface. The SO₂ in the atmosphere also promoted the occurrence of corrosion.