Abstract: Molten salt electrolysis has the advantages of high temperature resistance, radiation resistance and simple process, etc., which make it to be a popular method for extraction and separation elements in spent fuel reprocessing. With the recovery of uranium and transuranium elements, lanthanides, as the main components of fission products, gradually accumulate in molten salt, which seriously hinder the recovery of actinides. In order to promote the smooth recovery of actinides and realize the purification of molten salt, the lanthanides must be removed from the molten salt. Lu is the lanthanide element with the largest atomic number, and its deposition potential is closer to that of actinides. The electrochemical study of Lu is of great significance for the extraction of lanthanide elements and the separation of lanthanide and actinide elements. In this work, cyclic voltammetry and square wave voltammetry were used to analyzed the electrode reactions of Lu on W and Cu electrodes in LiCl-KCl eutectic salt at 773 K. It can be found that the reaction of Lu on W electrode is reversible process controlled by diffusion, and the diffusion coefficient of Lu(Ⅲ) in molten salt was calculated to be 1.32×10⁻⁵-1.03×10⁻⁵ cm²/s when its concentration was 2.38×10⁻⁵-7.00×10⁻⁵ mol/cm³. On Cu cathode, the formation of three Lu-Cu intermetallic compounds, CuLu、Cu₂Lu and Cu₅Lu, was confirmed by cyclic voltammetry, anode and cathode square wave voltammetry. The thermodynamic data such as equilibrium potential, activity and Gibbs free energy of standard molar formation for Lu-Cu intermetallic compounds were measured by open circuit chronopotentiometry, and the results show that the activity and Gibbs free energy of standard molar formation of Cu₅Lu are the smallest among Lu-Cu intermetallic compounds, indicating that Cu₅Lu is easier formed on Cu electrode. In addition, the kinetic parameters such as the exchange current density, charge transfer resistance and reaction activation energy of Lu(Ⅲ)/Cu₅Lu were calculated at different temperatures by polarization curves. With the increase of temperature, the exchange current density gradually increases, while the charge transfer resistance gradually decreases, demonstrating that the higher temperature is conducive to the electrode reaction. The separation of Lu was conducted by potentiostatic electrolysis at -2.2 V for 8 h, and the ICP-OES was used to measure the concentration of Lu(Ⅲ) in molten salt. The results show that the concentration of Lu(Ⅲ) in molten salt decreases gradually with the increase of electrolysis time. The extraction rate could reached 97.63% after electrolysis for 8 h. Besides, the results of XRD and SEM-EDS show that the product is composed of Cu and LuCu₂ phases. Thus, Cu electrode could be used to extract lanthanide Lu efficiently.