The invention relates to a 460MPa anti-seismic and fire-resistant building steel and a preparation method thereof, and belongs to the field of building steels. The 460MPa anti-seismic and fire-resistant building steel is prepared from the following components of 0.03 to 0.08% of C (carbon), 1.0 to 1.8% of Mn (manganese), 0.1 to 0.5% of Si (silicon), 0.2 to 0.7% of Cr (chromium), 0.1 to 0.3% of Mo(molybdenum), 0.05 to 0.12% of Ti (titanium), 0.04 to 0.12% of V (vanadium), 0.01 to 0.06% of Nb (niobium), 0.01 to 0.05% of Al (aluminum), 0.008% or less of P (phosphor), 0.002% or less of S (sulfur), and the balance of iron and unavoidable trace chemical elements. The preparation method comprises the following steps of performing conventional vacuum smelting, and casting into a blank; heating acasting blank, and performing conventional warming; coarsely rolling, and controlling temperature; finely rolling, and controlling finishing temperature; naturally cooling to certain temperature; performing water cooling until the temperature reaches room temperature; controlling the rolling and cooling, so as to obtain a martensite/bainite and ferrite double-phase tissue with fine crystal grains.The 460MPa anti-seismic and fire-resistant building steel and the preparation method have the advantages that by delivering in a TMCP (thermal mechanical control process) way, the complicated heat treatment technology is not needed; a process window is wider, the yield strength is greater than or equal to 460MPa, the tensile strength is 670 to 800MPa, the elongation rate at break is greater thanor equal to 26%, the KV2 at temperature of -40 DEG C is greater than or equal to 250J, and the yield ratio is smaller than 0.75; the 460MPa anti-seismic and fire-resistant building steel can be widelyapplied to high-rise and ultrahigh-rise buildings with high-strength, anti-seismic and fire-resistant steel requirements.