The invention discloses an activated stranded wire welding wire for increasing the penetration depth. The activated stranded wire welding wire is composed of an integrally-stranded multi-strand solid welding wire body, and an active agent with which the gaps of the stranded welding wire body are filled through extrusion. The cross section of the welding wire body is circular, and the diameter of the welding wire body ranges from 1.5 mm to 12.0 mm. The integrally-stranded multi-strand solid welding wire body is formed by stranding the solid welding wire in the middle axis, namely, the central wire, and 4 to 12 strands of solid welding wires around the central wire, namely, the peripheral wires. The active agent is composed of, by mass, 50% to 60% of SiO2, 10% to 20% of TiO2, 10% to 20% of Cr2O3, 0% to 12% of NaF, 0% to 11% of LiF, 0% to 8% of potassium fluozirconate, 0.1% to 1.0% of sodium stearate and 0.1% to 1% of yttrium oxide. The welding wire is large in welding penetration depth, an electric arc is stable, a weld joint is well formed, and the welding wire can have any length, is suitable for continuous automatic welding and can be used for electric arc welding, submerged-arc welding and electroslag welding of gas protection.