The invention relates to welding wires, in particular to high-strength welding wires needing hardening and tempering after welding, comprising the following chemical components by weight percent: 0.03-0.12 wt% of C, 0.30-0.80 wt% of Si, 1.2-2.2 wt% of Mn, 1.0-2.0 wt% of Ni, 0.05-0.30 wt% of Cu, 0.10-0.50 wt% of Cr, 0.20-0.80 wt% of Mo, 0.03-0.20 wt% of Ti, equal to or less than 0.015 wt% of S, less than or equal to 0.020 wt% of P, and the balance Fe and inevitable impurity elements. As for the welding wires after rich Ar gas shielded welding, under the thermal refining state, the mechanical property of the obtained welded metal is follows: yield strength ReL is equal to or greater than 630MPa, tensile strength Rm is equal to or greater than 780MPa, elongation A is equal to or greater than 20%, and absorbed energy Akv is equal to or greater than 60J under the temperature of -40 DEG C. The welded metal of the welding wires has high strength, good low-temperature toughness and favorable welding technological property after hardening and tempering.