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Low-surface-treatment coatings, also known as surface-tolerant coatings, represent the best example of the development that has taken place in combination with coating applications. From a fundamental principle perspective, low-surface-treatment coatings possess good permeability; they can penetrate and seal off rust layers as well as the reactive groups within the coating. This allows the active pigments to react with the reactive and harmful components in the rust, forming stable inhibitory compounds that turn the rust into a special protective layer. In addition to penetration-type, stable-type, and conversion-type low-surface-treatment coatings, functional low-surface-treatment coatings with additional advantageous properties have been developed at home and abroad in recent years. Their features are as follows: (1) Environmentally friendly, solvent-free, with 100% solid content, and no VOCs or harmful gases are released during application ； The coating is non-toxic and flame-retardant. (2) The coating undergoes a chemical reaction with metal and concrete, resulting in high adhesion on wet surfaces (12–17 MPa on wet/dry metal surfaces, 8–11 MPa on wet/dry concrete surfaces). (3) Lower requirements are imposed on surface treatment (sandblasting at Sa 1–2 level, manual grinding at St 2 level); it is possible to carry out work in an environment with a relative humidity of over 90%, where the substrate is moist and has surface rust or fleeting rust, with no limit regarding the dew point. (4) The solvent-free coating is dense, free from defects such as pinholes, and of high quality; it exhibits excellent resistance to salt spray penetration and chemical corrosion ； In harsh marine and atmospheric environments such as C4 and C5, its service life can exceed 15 years. (5) It has excellent coating performance on sharp edges, allowing a coating coverage of 90% for both edges and welds in a single application. (6) Compatible with various cathodic protection measures.