The effects of metal calcium and CaO crucible on deep deoxidation and desulfurization of cast superalloy K417G were studied by vacuum induction melting.Results showed that Ca can achieve the effect of deep deoxidation and desulfurization, the oxygen content decreased from 0.0013% to 0.0006%, the sulfur content decreased from 0.0007% to 0.0002%.The equilibrium relationship between measured w [Ca] -w [S] in the alloy is basically the same as that of the thermodynamic calculation.In addition, the effect of deoxidation and desulfurization of CaO crucible is obvious, oxygen content can be reduced to 0.0006%, sulfur content can be reduced to less than 0.0002%, the reduction of sulfur content is related to the formation of mCaO.nAl2O3slag in the inner wall of CaO crucible, thus realizing deep desulfurization.