The invention provides a gas-shielded high-toughness solid welding wire which is prepared from the following chemical components by mass percentage: 0.10-0.12% of C, 0.40-0.50% of Si, 0.60-0.70% of Mn, less than or equal to 0.010% of S, less than or equal to 0.015% of P, 1.2-1.5% of Cr, 0.50-0.60% of Mo, less than or equal to 0.02% of Ni, less than or equal to 0.03% of Cu, 0.030-0.080% of Al, less than or equal to 0.0040% of Sb, less than or equal to 0.0050% of Sn, less than or equal to 0.0050% of As, and the balance Fe. According to the invention, welding line metal with low impurity content is obtained by adopting welding wires with low S, P, Sb, Sn and As contents, and the content and proportion of Si and Mn are adjusted, thus playing a good deoxidization role and being favorable for uniform texture of the wielding line; by adding Al element, a strong deoxidizing effect can be achieved, the grains can be refined, and the low-temperature impact toughness of the welding line metal can be remarkably improved; and the gas-shielded high-toughness solid welding wire is excellent in technological performances, steady in welding arc, little in welding smoke and splashing and attractive in formed welding lines.