Disclosed are a magnesium die casting alloy, and an alloy composition for improving thermal conductivity and electrical conductivity. A magnesium die casting alloy includes an amount of about 0.5 to 2.0 wt % of aluminum (Al) and the balance magnesium (Mg), based on the total weight of the magnesium die casting alloy. Accordingly, an alloy, which has high thermal conductivity and electrical conductivity as compared to a conventional AZ91D magnesium alloy, is obtained.