[en] The effect of small addition of Al on the electrochemical performances was investigated by open circuit potential and Tafel Extrapolation method. The results show that open circuit potential reveals as-cast Mg containing Ca alloys with minor content of Al maintained highly negative potential with the range of -1.68 to -1.63 V_SCE in comparison to both pure Mg (-1.60V_SCE) and commercial high potential Mg content. Corrosion rate for the as-cast samples remains higher (30-17 mpy) than pure Mg (3 mpy) and commercial high potential Mg anode (14 mpy). The increasing small content of Al results in the reduction of corrosion rate significantly. Therefore, it proves that the performance of Mg containing Ca alloy is strongly influenced by the concentration of Al. (author)