The invention belongs to the technical field of welding materials, and in particular relates to a gas-shielded solid welding wire for ultra-high-strength construction machinery steel plates, which comprises the following components in terms of mass percentage: C: 0.08-0.12%, Si: 0.70-0.90%, Mn: 1.65-1.85%, Cr: 0.45-0.65%, Ni: 2.3-2.5%, Mo: 0.40-0.70%, Ti: 0.08-0.15%, Zr: 0.04-0.08%, Nb: 0.05-0.10%, B : 0.004~0.006%, S: 0.005~0.015%, P≤0.010%, the balance is iron and unavoidable impurities. The present invention also provides the application of the above-mentioned gas-shielded solid welding wire, which is used for welding ultra-high-strength engineering machinery steel plates with a tensile strength of 960 MPa. The weld seam formed by welding with the solid welding wire provided by the invention has the advantages of good low-temperature impact toughness, low yield ratio, high strength, and beautiful shape; and the welding spatter is small, and the welding process performance is excellent; the use of argon-rich (80%Ar+20 %CO 2 ) gas shielded welding, the yield ratio of the deposited metal is ≤0.9, which is suitable for the welding of ultra-high-strength engineering machinery steel plates such as Q890 with a tensile strength of 960MPa.