The composition of different Mg alloys is known to affect their current capacity, potential, and anode efficiency. Many alloying elements have been used in attempts to improve the electrochemical properties of magnesium anodes. Significant improvements of electrochemical properties have been achieved by controlling the adverse effects of impurity elements such as Fe, Ni, Cu with alloying elements. Out of many elements, Ca is considered as a very effective element that can improve the electrochemical properties of Mg-alloys because of its relatively low potential in comparison with specified elements such as Mn, Al, Zn in high Mn alloys or AZ63 alloys with the effect of grain refining and solid solution of minor element in Mg. Ca has recently been used as a common inhibitor for the ignition of molten Mg alloys. However, the fluidity of pure Mg is markedly decreased with increasing Ca content. Ca addition is responsible for making the casting of Mg alloys from Mg melts difficult at desirable pouring temperatures. In this study, our target is to investigate the optimum alloying composition of good cast ability and high electrochemical properties in given experimental condition.