The microstructure characteristics and properties of TIG welded joint of C-276 alloy are studied by OM and other technologies,the corrosion resistance of the weld and base metal in acid and neutral solutions are also investigated. The results show that the microstructure of weld is austenite, and its appearance is columnar and equiaxed. The microstructure of HAZ consists of coarsen austenite and blocky and strip intermetallic compounds. The hardness test shows that the weld microhardness is minimum and about 260 HV. The electrochemical testing indicates that the corrosion resistance of the weld in an acidic environment is weaker than that of the base metal,and the corrosion current density and corrosion rate of the weld are higher than that of the base metal. However, in a neutral environment,the corrosion resistance of the weld is similar to that of the base metal.