Compositions and usage method of Si-Ba inoculant,Si-Sr inoculant,Si-Zr inoculant,Si-Ca inoculant as well as RE-containing inoculant was described.The inoculation effect mechanism of above mentioned inoculants was discussed.It was believed that by selecting proper inoculant for the high strength gray iron,nodular iron and vermicular iron,it is possible to reduce production cost,improve castings quality,save energy,as well as to be beneficial to environment protection.