A gas-shielded flux-cored wire with recyclable welding slag belongs to the welding field. In the invention, the skin of the gas-shielded flux-cored wire is made from a mild steel strip, and welding slag powder is partially or completely instead of natural rutile, thus the purposes of saving the resource and reducing the cost are achieved. The powder of the flux-cored wire comprises the following chemical components in percentage by weight: 15-35% of the welding slag powder of the flux-cored wire (including 20-65% of TiO2, 5-15% of MnO, 5-15% of MgO, 5-15% of SiO2, 1-10% of Fe2O3 and 1-10% of Al2O3), 15-35% of TiO2, 2-7% of Si, 3-8% of Mn, 0.5-5% of Al-Mg, 0-5% of Na, 0-5% of K, 1-5% of Mg and the balance of ferrous powder. When the flux-cored wire manufactured by adopting the welding slag powder is applied to welding, the gas-shielded flux-cored wire has the advantages of excellent technical performance of welding and omnibearing welding adaptability, attractive appearance good humidity resistance, low content of diffusible hydrogen in a welding seam, excellent crack resistance, high connection strength and good low-temperature impact toughness.