The invention discloses high-toughness high-mirror pre-hardened die steel and a manufacturing process thereof, and relates to the technical field of die steel. The high-toughness high-mirror pre-hardened die steel comprises raw materials including, by weight, 0.08-0.18 part of C, 0.1-0.5 part of Si, 2.2-3.0 parts of Mn, 2.5-3.3 parts of Cr, 0.1-0.5 part of Mo, 0.7-1.5 parts of Ni, 0.1-0.25 part ofV, 0. 01-0.02 parts of P, 0.0005-0.002 part of S and the balance Fe. Preparation processes of the mold steel comprise ingredient smelting, ladle refining, vacuum degassing, pouring, electroslag remelting, forging, annealing and finally quenching and tempering heat treatment; and the tempered structure is mainly tempered martensite and retained austenite. By means of the high-toughness high-mirrorpre-hardened die steel and the manufacturing process of the high-toughness high-mirror pre-hardened die steel, the hardenability of the die steel is fully improved by using Mn-Cr-Ni-Mo composite alloying, the hardness and uniformity of the die steel are ensured, the ductility, toughness and strength of the die steel are improved, the pre-hardened die steel is uniform in hardness, the hardness is38-43HRC, the polishing performance is high, the impact toughness is excellent, the hardenability is excellent, and meanwhile, good weldability and corrosion resistance are achieved.