In order to solve the corrosion issues that occur in the weld zone (WZ) of zirconium material applied in the industrial community, X-ray diffraction (XRD), electrochemical analysis, scanning electron microscope (SEM) and energy dispersive spectrometer (EDS) were used to investigate the microstructure and corrosion resistance of the zirconium butt joint by tungsten inert gas (TIG) welding. Also, the mechanism of corrosion was discussed. It is found that the corrosion pattern of zirconium butt joint is intergranular corrosion. The factors that cause intergranular corrosion are the inadequate protection of argon and a trace amount of oxygen existing in the soldering wires, which facilitates the generation of zirconium composite oxides that result in the electrochemical inhomogeneity between crystal boundaries and particles. Consequently, the dissolve current density of crystal boundaries is larger than that of the grains, which leads to intergranular corrosion