Abstract: In order to achieve the large-scale, low-energy and high efficiency in the preparation of the rare earth alloy by the molten salt electrolysis, 25 kA electrolysis current was adopted in the preparation of praseodymium neodymium alloys in fluoride salt system. Through the industrial practice, the impacts of electrolytic tank structure, electrolytic temperature, and current density, electrolyte composition, stirring furnace operation and crucible material on the quality of electrolytic products were explored. Experiment establishes the technologic parameter for the effective control of non-rare earth impurity in the preparation of praseodymium neodymium alloy by 25 kA molten salt electrolysis.