In this study, UNS N10003 Hastelloy is welded using laser wire‐filling welding. The welded joint exhibits favorable tensile strength at room and high temperatures. A molten salt corrosion experiment is performed, and it is discovered that the corrosion depth increases gradually as corrosion progresses, although the growth rate decreases. When the corrosion time reaches 96 h, the corrosion depths of the weld bead and base metal are 23.39 and 24.71 μm, respectively, indicating their similar corrosion resistance. The main corrosion mechanism of N10003 Hastelloy in molten salt is the diffusion of Cr and Mo. Ni3Fe and pure Ni phases appear near the outer surface area after corrosion, which can reduce the corrosion rate.