The static constant corrosion tests on Fe-B eutectic alloy are investigated in liquid zinc at 500°C. The systematic observation and research of the corrosion layer are performed using SEM, TEM, XRD. The results show that corrosion resistance of Fe-B eutectic alloy in liquid zinc is perfect. Corrosion products are Fe3B and FeZn7. The corrosion layer is regular, the structure of which is hollow dendritic skeleton and the thickness of which increases with the corrosion time extending. Corrosion process is that the interdiffusion of ferro and zinc atomic results in corrosion layer formation and the corrosion layer ruptures and dissolves under the action of thermal stress and impact stress of liquid zinc. The process repeating leads to the failure of the matrix eventually.