A welding wire is provided with a hollow section for accommodating flux. The flux has a composition including: Mn: 5-20%, Si: 1-15%, TiO2: 5-25%, SiO2: 0.1-10%, Mo: 0.1-5% by weight, the balance being iron. When welding low alloy high strength steel by using the welding wire, the slag on the welding bead can be easily cleaned and a smooth surface can be formed on the welding bead which makes it easier to galvanize a zinc layer over the surface of the welding bead. The welding wire provides better welding operation performance and generates less welding spatters.