The electrochemical formation of RE-Ni (RE=Pr, Nd and Dy) alloys was investigated in molten LiF-CaF2-REF3 systems at 1123 K. Cyclic voltammetry and open-circuit potentiometry indicated the formation of several phases of RE-Ni alloys. The formations of RENi2, RENi3 and RENi5 were confirmed by XRD and SEM/EDX. The formation potential for each alloy phase has been determined. The maximum Dy/Nd atomic ratio in the alloy estimated by EDX was 5.6. In molten LiCl-KCl-RECl3 (RE=Nd and Dy) systems at 723 K, the maximum Dy/Nd mass ratio in the alloy determined by ICP-AES was 121, indicating a high potentiality for the new separation/recovery process of Nd and Dy.