The invention discloses high-toughness mining chain steel and a manufacturing method thereof. The high-toughness mining chain steel comprises the following components in percentage by weight: 0.20-0.28% of C, 0.01-0.40% of Si, 0.50-1.50% of Mn, less than or equal to 0.015% of P, less than or equal to 0.005% of S, 0.30-2.00% of Cr, 0.50-2.00% of Ni, 0.10-0.80% of Mo, 0.01-0.30% of Cu, 0.01-0.05% of Al, 0.001-0.10% of Nb, 0.001-0.10% of V, less than or equal to 0.00018% of H, less than or equal to 0.0150% of N, less than or equal to 0.0020% of O and the balance of Fe and inevitable impurities. The manufacturing process comprises the working procedures of smelting, refining, vacuum treatment, casting, heating, forging or rolling, quenching and tempering heat treatment and the like. The chain steel has high strength and good impact toughness, ductility and percentage reduction of area, can resist stress corrosion cracking, has good weather resistance, wear resistance and fatigue resistance, and can be used for engineering machinery, ocean engineering and other occasions needing high-strength and high-toughness steel.