Electrochemical behavior of Mg, Li and Sn on tungsten electrodes in LiC1-KC1-MgCI2- SnC12 melts at 873 K was investigated. Cyclic voltammograms （CVs） showed that the underpotential deposition （UPD） of magnesium on pre-deposited tin leads to the formation of a Mg-Sn alloy, and the succeeding underpotential deposition of lithium on pre-deposited Mg-Sn alloy leads to the formation of a Mg-Li-Sn alloy. Chronopo- tentiometric measurements indicated that the codepositon of Mg, Li and Sn occurs at current densities more negative than -1.16 A.cm-~. X-ray diffraction （XRD） in- dicated that Mg2Sn phase is formed via galvanostatic electrolysis. The element Mg distributes homogeneously and Sn locates mainly on the grain boundaries in the Mg- Li-Sn alloy.
