The electrodeposition of aluminium and magnesium in lithium chloride-sodium chloride (mass 5:1) melt at 700 degrees C has been studied using cyclic voltammetry, square wave voltammetry and chronopotentiometry. The reduction of aluminium and magnesium ions on tungsten electrode are both reversible processes, with three and two electrons exchanged: Al(3+)+3e -> Al, Mg(2+)+2e -> Mg. The diffusion coefficients of Al(3+) and Mg(2+) were determined as 2.72 X 10(-5) cm(2) s(-1) and 1.58 x 10(-4)cm(2) s(-1) respectively. A laboratory test of the direct production for the Mg-Al alloy was performed to show the feasibility of electrochemical co-deposition of magnesium base alloys.