The electrochemical reduction process of Zr(Ⅳ) was studied at molybdenum electrodes in K2ZrF6-LiCl-KCl molten salt at 923 K by transient electrochemical techniques, such as cyclic voltammetry, chronopotentiometry and chronoamperometry. The experimental results show that Zr(Ⅳ) was reduced to Zr metal by a two-step mechanism corresponding to the Zr(Ⅳ)/Zr(Ⅱ) and Zr(Ⅱ)/Zr transition. The intermediate product was identified as ZrCl2 by X-ray diffraction. The chronoamperometric studies indicate that nucleation polarization existed during the electrodeposition process of zirconium at molybdenum electrode. This polarization is an instantaneous nucleation process