The isothermal corrosion testing, microscopic examination and the performance of Fe₃Si alloy as materials of construction for bath hardware in continuous hot-dipping lines were studied. The corrosion of Fe₃Si alloy in molten zinc was controlled by attacking the grain boundaries preferentially. Aluminum reacted with iron of Fe₃Si alloy firstly while the samples were immersed in molten zinc, although aluminum contents in the molten zinc were very low. The phase of reaction product was thought to be Fe₂Al₅. The corrosion rate of the Fe₃Si alloy in molten zinc was determined to be approximately 2.9×10^-3 mm/h, therefore the liquid zinc corrosion resistance of Fe₃Si alloy was very weak.