The invention belongs to the field of welding materials, and particularly relates to a nickel-based self-fluxing hard-facing flux-cored wire for plasma surfacing. The flux-cored wire comprises all elemental components including, by weight, 0.3% to 1.0% of carbon, 14% to 19% of chromium, 3.5% to 5.0% of silicon, 3.0% to 4.5% of boron, 0% to 6% of iron and the balance nickel. The wire is prepared through the following method: a certain amount of chromium powder, boron powder, nickel powder and silicon and iron powder are weighed and sufficiently stirred to be evenly mixed, a Ni80Cr20 stainless steel strip bent into a U shape is filled with the mixed powder, curling and opening sealing are carried out, the strip is drawn down to the diameter of 2.0 stage by stage through a wire drawing machine, and the flux-cored wire is obtained. The nickel-based self-fluxing hard-facing flux-cored wire has the beneficial effects of being low in production cost, good in self-fluxing, high in surfacing efficiency, high in cladding rate and the like, and is suitable for plasma surfacing; a surfacing layer is large in combination strength and high in hardness and has the extremely high hard-faced wear resistance, abrasive particle wear resistance and erosive wear resistance properties.