he electrochemical deposition of aluminium from NaCl-AlCl3 molten salt system has been studied by using cyclic voltammogram.In the basic salts the species reduced at the cathode are AlCl4 ions,while in the acidic salts the species reduced are Al2Cl7 ions.There are equilibrium reactions between the ionic species,which influence the reduction of aluminium at the cathode.The reduction reaction of Al2Cl7 is quasireversible,and the reduction mechanism is very complicated.There may be some pre-chemical step or camo-catalytic reaction mechanism.