Many experimental results confirm that electromagnetic stirring (EMS) has a good purification effect on the melts, either degassing or removing inclusions, but the mechanism of electromagnetic purification still needs to be further explored. This paper takes M174 alloy as an example, and carries out a more in-depth study on the purification effect of electromagnetic field on the basis of numerical simulation, focusing on the amount of hydrogen present in the ingot, the enhancement effect of electromagnetic field stirring on the mechanical properties of the melt was investigated in terms of the treatment temperature, and the current intensity during electromagnetic stirring. The results show that the tensile strength and elongation of the alloy reached 195.3 MPa and 0.69% after electromagnetic stirring at a current intensity of 60 A, which are very close to the theoretical properties of the alloy of 200.3 MPa and 0.74%, respectively. At the same time, the effect of electromagnetic stirring on the presence of oxides and double oxide film in the melt is slightly explored.