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In recent years, biodegradable magnesium alloys have attracted considerable attention in medical devices, such as permanent implants and stents. However, poor corrosion resistance is a major problem limiting the practical application of magnesium alloys. In this study, Mg _67 Zn _28 Ca _5 alloys were prepared via two different methods, namely, vacuum induction melting and ulfur hexafluoride shielded melting. The effect of melting method on the bio-corrosion resistance of MgZnCa cast magnesium alloy was also studied. The microstructure and phase composition of Mg _67 Zn _28 Ca _5 alloys were investigated by optical microscopy and X-ray diffraction. The element distribution and surface morphology of Mg _67 Zn _28 Ca _5 alloys were examined by scanning electron microscopy and energy-dispersive spectroscopy. The corrosion resistance of Mg _67 Zn _28 Ca _5 alloys was measured via electrochemical and immersion tests. Results showed uniform composition of the Mg _67 Zn _28 Ca _5 alloy melted by vacuum induction. Immersed in the simulated body fluid, the corrosion rate of Mg _67 Zn _28 Ca _5 by vacuum induction melting (0.2618 mm/ a ) was lower than that by ulfur hexafluoride shielded melting (0.9686 mm/ a ); the corrosion potential of Mg _67 Zn _28 Ca _5 melted by vacuum induction (−1313 mV) was nobler than that by ulfur hexafluoride shielded melting (−1483 mV); the corrosion current of Mg _67 Zn _28 Ca _5 by vacuum induction melting (1.202 × 10 ^−5 A) was lower than that by ulfur hexafluoride shielded melting (4.332 × 10 ^−5 A). The Mg _67 Zn _28 Ca _5 by vacuum induction melting showed uniform corrosion behavior.