The two‑layer structure composed of a glass film and an inorganic insulating coating on the surface of grain‑oriented silicon steel sheets is the key to ensuring the insulation resistance of transformer cores, reducing power loss, and improving processability and corrosion resistance. Tight adhesion between the coating and the substrate is the core prerequisite for achieving the above properties. In this paper, the coating adhesion mechanism is explained from two dimensions: physical mechanisms (mechanical interlocking, wetting, and weak boundary layer theories) and chemical mechanisms (chemical bonding and acid‑base theories). The influencing laws of glass film quality, surface cleaning effect, coating solution wettability, chemical bonding effect and other factors on coating adhesion are systematically analyzed, and the development status of testing standards and devices for the adhesion of grain‑oriented silicon steel is summarized. The results show that preparing high‑quality glass films, optimizing coating solution components and the size and morphology of colloidal silica, and improving surface cleaning quality are the keys to obtaining excellent coating adhesion performance. Finally, it is pointed out that there is an urgent need to formulate an internationally recognized testing standard for the adhesion of grain‑oriented silicon steel that is accepted by both upstream and downstream industries.