Chemical distribution of metallic elements between molten salt and liquid Mg metal has been investigated as a fundamental study on the preparation of Mg alloys by using molten salt. A purified eutectic mixture of MgCl2-NaCl-KCl was melted with Mg metal, and CaCl2, MnCl2 or LaCl3 was added to the molten salt. The contents of Na, K and Ca in Mg metal did not change remarkably even after contact with the molten salt consisting of these elements. Manganese moved from the molten salt with MnCl2 to Mg metal, and La also transferred from the molten salt with LaCl3 chemically. However, the migration of these elements were slow, and some factors should affect their chemical distributions.