Abstract: Aluminum-magnesium alloys were prepared through molten salt electrolysis from magnesium oxide. In the test, the liquid Al was taken as cathode with graphite as anode to produce CO and CO2 instead of a big amount of toxic or harmful gases released from conventional magnesium electrolysis. It was revealed that the content of Mg in Al increases gradually and up to 1%-5wt% with lengthening electrolyzing time, and the solubility of MgO can be improved by over 30% if 10wt% KC1 is added into electrolyte. CeF2 can lower the initial crystallization temperature of electrolyte, while the viscosity of electrolyte can be increased. The maximum current efficiency comes up to 74.5% within the first 45 min, then it decreases sharply, even below 40% after 2 hours.