Electrochemical codeposition of Mg-Li alloys on molybdenum electrodes was investigated in LiCl-KCl (50 wt.%:50 wt.%) melts containing different concentrations of MgCl_2 at 973 K. Cyclic voltammograms show that the underpotential deposition of lithium on pre-deposited magnesium leads to the formation of liquid Mg-Li alloys. The deposition potentials of Mg(Ⅱ) and Li(Ⅰ) ions gradually near each other with MgCl_2 concentration decreasing. Mg-Li alloys with typical α + β phases could be obtained by potentiostatic electrolysis from LiCl-KCl melts containing 5 wt.% MgCl_2 at -2.25 V vs. Ag/AgCl (cathodic current density 1.70 A·cm~(-2)) for 2.5 h. Α phase, α + β phases, and β phase Mg-Li alloys with different lithium contents were obtained by potentiostatic electrolysis from LiCl-KCl melts with the different concentrations of MgCl_2. The samples were characterized by X-ray diffraction and scanning electron microscopy.