The present invention relates to a self-protection flux-cored welding wire for full-position and high-toughness welding. A flux core comprises the following components in percentage by weight: 2 to 7 percent of Mn, 3 to 6 percent of Ni, 1 to 10 percent of Al, 1 to 20 percent of Mg, 1 to 10 percent of carbonate, 10 to 60 percent of fluoride, 0.5 to 8 percent of TiO2, 0.5 to 6 percent of SiO2, and the balance of iron powder; and the flux core accounts for 16 to 30 percent of the total weight of the welding wire. The self-protection flux-cored welding wire has the advantages of good toughness and plasticity of weld metals, little splash and good full-position welding performance, and remarkably improves the slag detachability and weld formation property.