FeSiBa inoculant is an additive in foundry process.It can promote graphitization, reduce the tendency of chill, improve the morphology and distribution of graphite, increase the number of eutectic groups and refine the matrix structure. It has a good effect in a short time (about 5-8 minutes) after inoculation. For gray iron castings, the main function of inoculation is to promote graphitization, reduce the tendency of white mouth, increase the number of eutectic groups, promote the formation of A-type graphite and fine pearlite. For ductile cast iron, the main function of inoculation treatment is to promote the evolution of graphite, improve the inhibition of eutectic permeability, and increase the number of graphite balls per unit area The results show that the microstructure of ductile cast iron is more uniform and the plasticity and toughness of ductile iron are improved.