The invention provides hot stamping die steel and a production method thereof. The hot stamping die steel is composed of, by weight, 0.45-0.50% of C, 0.1-0.3% of Si, 0.1-0.3% of Mn, 2.0-2.3% of Cr, 2.3-2.5% of Mo, 0.8-1.0% of V, smaller than or equal to 0.03% of P, smaller than or equal to 0.03% of S and the balance Fe and other inevitable impurities and meets the relational expressions that Mo / Cr=1-1.25 and V / Cr=0.35-0.43. By means of the electroslag remelting process, the ultrafine thermal treatment process, the vacuum thermal treatment process and the plasma nitriding surface treatment process, the produced and obtained hot stamping die steel is low in cost and high in comprehensive performance; the hot stamping die steel has a thermal conductivity coefficient of 34.3 W / m.k, quenching and tempering hardness of 50-53 HRC, ballistic work of 180-210 J, surface hardness of 850-1040 HV0.3 and diffusion thickness of 230-300 microns, and a white bright layer is ceaseless after nitriding.