The corrosion problems in petrochemical, marine, pipeline, and other industries are becoming more severe, and the economic losses and corrosion prevention costs are increasing. A cost-effective and excellent corrosion-resistant coating material to promote the development of the petrochemical industry is of great importance. Enamel is an inorganic material with good chemical stability, bonding with metal, good economy and simple preparation process, which is expected to be an excellent material for anti-corrosion coating. The use of enamel as a protective coating has been tried in the above areas and has shown relatively excellent protection. However, there are still some shortcomings, such as insufficient corrosion resistance in strong acid and alkaline environments, and the negative effect of the pore structure in the coating on corrosion resistance, while the high-temperature sintering process also affects the mechanical properties of the metal substrate. In this work, the structural characteristics and corrosion resistance mechanisms of enamel as an anti-corrosion coating are discussed, and the improvement methods used in different corrosive media are summarized.