The invention provides a submerged arc welding flux-cored wire which comprises a steel belt and a flux core. Chemical components of the steel belt comprise, by weight, smaller than or equal to 0.02% of C, 0.2-1.2% of Mn, 0.3-1.8% of Si, 22-28% of Cr, 2-8% of W, 0.2-0.4% of Cu, 0.1-0.3% of V, smaller than or equal to 0.005% of S, smaller than or equal to 0.006% of P and the balance Fe. The components of the flux core comprise, by weight, 20-35% of marble, 15-28% of fluorite, 7-12% of mica, 6-14% of titanium dioxide, 2-8% of ferrovanadium, 2-6% of silicon iron, 2-12% of ferrotitanium, 13-17% offerro-boron, 2-8% of ferro-molybdenum, 3-12% of graphite and the balance chromium iron. By the adoption of the welding wire, while the hardness of overlaid metal can be improved, toughness and crack resistance of the metal are improved, the two aspects of metallurgy and the technology are improved, the high toughness and crack resistance of the overlaid high-hardness metal are improved, meanwhile,the good welding technology performance is ensured, slag removal is easy, splashing is avoided, the hardness is high, and the wear resistance is excellent.