The quality of the galvanized layer can be evaluated by the weight of the zinc plated on the substrate, the bonding force between the galvanized layer and the substrate, and the uniformity of the coating. The uniformity of the zinc layer is an important quality indicator of the zinc coating. In general, the corrosion always starts at the thinnest part of the zinc layer and spreads around, resulting in rust, broken wires and affecting the service life. For the coating weight and bonding strength, each standard has clear regulations, but the uniformity is different. In the 1970s, the ISO standard and the standards of various countries in the world generally stipulated that the copper sulfate test should be used for inspection. By the 1980s, with the exception of Japan and the former Soviet Union, ISO standards and standards around the world no longer adopted this method. Although our country has retained this method in some standards such as GB/T15393-94 "Steel wire galvanized layer" in the form of "can be carried out by mutual agreement", most of them are no longer adopted. However, the old zinc coating uniformity detection method has been abandoned but no corresponding new methods have been established. In addition, there is no uniform definition and requirement for uniformity, so that some producers do not monitor and detect the uniformity of the coating well. , So as to affect the further improvement of product quality