Fe-Cr-B alloy has excellent corrosion resistance to molten aluminum，but its toughness is poor.In order to improve the toughness of Fe-Cr-B alloy，the influence of Ce addition （0~0.92%，mass fraction） on the microstructure，mechanical properties and corrosion resistance of Fe-Cr-B alloy in molten aluminum at 750℃ was investigated.The results show that the addition of Ce changes the boride structure in Fe-Cr-B alloy from a continuous network，dendritic and long rod-like structure to a short rod-like and block structure with less interconnection.With the Ce content increases，the alloy's impact toughness gradually increases，and the corrosion resistance to molten aluminum increases first and then decreases.The uniformly distributed short rod-like boride can improve the alloy's impact toughness while maintaining excellent corrosion resistance to molten aluminum.The Fe-Cr-B alloy with 0.59% Ce has the best comprehensive properties，its impact toughness is 187.97% higher than that of Ce-free，and its corrosion resistance to molten aluminum reaches 5.9 times that of typical die steel H13.