With the construction of more and more super high-rise and large-span building projects, higher requirements are put forward for the high strength, long life and service safety of building structural steel. The development of 460 MPa anti-seismic, corrosion-resistant and fire-resistant composite building steel has broad market application prospects. The steel has the characteristics of high strength and toughness, low yield ratio, lamellar tearing resistance and good weldability, as well as fire resistance and weather resistance. It can reduce the thickness of steel used in high-rise buildings, save the amount of steel, and ensure the long-term bearing capacity of highrise buildings in fire without using fireproof coating. It can be widely used in super high-rise buildings, large factories and other steel structures with high fire resistance and weather resistance. Based on the comparative analysis of the key technologies of 460 MPa anti-seismic, corrosion-resistant and fire-resistant building steel, the process of hot metal KR desulfurization, converter smelting, LF + VD refining, water cooled ingot mold casting of copper plate mould, ingot reheating, rolling mill forming and QLT heat treatment was used for trial production. In the aspect of composition design, the core is the composite microalloying design of fire resistance and corrosion resistance, taking into account its strengthening function, grain refinement function, corrosion resistance function and nano precipitate precipitation behavior. In order to improve its welding performance, the carbon equivalent is controlled within 0. 55, and the composite functions of high strength, toughness, fire resistance and corrosion resistance are realized by reasonable proportion of Cu, Cr, Ni and Mo. At the same time, in order to reduce the cost, the precious alloy element molybdenum is controlled below 0. 30%. In the aspect of molten steel smelting, ultra-low P, ultralow S, ultra-low O and high purity of steel can be achieved through fine material feeding and pure steel smelting technology. The original billet was formed by an improved water-cooled ingot mold with copper plate mold, and the micro defects in the ingot were avoided by directional solidification technology. In the rolling process, the surface hardening is promoted by hard shell rolling, so that the rolling force can penetrate into the center of the steel plate, and the microstructure can be refined uniformly while improving the internal quality. In the heat treatment process, the proper combination of hard and soft phases is achieved by quenching in the two-phase zone, so as to reduce the yield strength ratio, refine the grains and improve the impact toughness. Through the process design of composition design, converter smelting, water cooling mold casting, rolling and off-line heat treatment, 460 MPa anti-seismic and anti-corrosion refractory steel plate was developed. Its yield strength is controlled at 500- 520 MPa, tensile strength is controlled at 630-650 MPa, elongation is 24% -27%, yield ratio is 0. 79-0. 81, average reduction of area in thickness direction is 70%, and its yield strength is 339-367 MPa after holding at 600 ℃ for 3h. The longitudinal impact energy at 40 ℃ is more than 200 J, and the atmospheric corrosion resistance index is more than 7. 5. The maximum thickness of steel plate is 150 mm, the maximum width is 3 800 mm and the maximum length is 120 000 mm.