Magnesium will be a very promising anode material for primary high energy density batteries, in the event that the corrosion of Mg electrode in aqueous electrolyte is effectively inhibited. Double liquid electrolyte (DLE) is designed and it reduces the corrosion significantly. DLE consists of an aqueous phase and an organic phase, which is immiscible with the former. Cathodic and anodic reactions proceed in the two phases separately, therefore Mg electrode no longer contacts with aqueous electrolyte. Anodic efficiency of pure Mg is above 90% in DLE, much higher than in single aqueous electrolyte.