Ultra-thin steel structural fire-resistant coating means the coating thickness is within 3 millimeters (inclusive of 3 millimeters), offering excellent decorative effects. The expansion foam can expand at high temperatures, and the fire resistance limit of the steel structure is generally 2 hours for the fire-resistant coating. This type of fire-resistant coating is typically solvent-based, featuring excellent adhesion strength, good weather resistance and water resistance, good leveling properties, and good decorative qualities. It slowly expands and foams when exposed to fire, forming a dense and hard fire-resistant insulation layer. The fire-resistant layer has strong impact resistance, delays the temperature rise of the steel, and effectively protects the steel components. The ultra-thin expansion steel structural fire-resistant coating can be sprayed, brushed, or rolled on, and is generally used for building steel structures with fire resistance requirements within 2 hours. A new type of ultra-thin steel structural fire-resistant coating with fire resistance of up to or exceeding 2 hours has emerged, primarily composed of special structures of poly(methyl methacrylate) or epoxy resin, with amino resin and chlorinated paraffin as the base materials. The mixture includes flame-retardant systems such as high-polymer ammonium polyphosphate, pentaerythritol, and melamine, along with inorganic fire-resistant materials like titanium dioxide and wollastonite, and 200# solvent oil as the solvent compound. Various types of light steel structures, grids, and other fire-resistant coatings are used for fire protection. Due to the ultra-thin coating of this fire-resistant coating, the use of thicker, thin steel structural fire-resistant coatings is significantly reduced, thereby lowering the overall project cost. The steel structure is effectively fire-resistant, with excellent fire protection effects.