Abstract: A novel method for preparing neodymium oxide by cationic membrane electrolysis was proposed in this paper. With a neodymium chloride solution as the raw material, neodymium hydroxide was precipitated by electrolysis conversion, and the neodymium oxide was obtained by calcination. The results of cyclic voltammetry and thermodynamic analysis show that the preparation process of neodymium hydroxide by electrolyzing a neodymium chloride solution involves the coupling of electrolytic deacidification and neodymium hydroxide precipitation, and the two processes promote and restrict each other. The influences of the initial concentration, current density and electrolysis time of the neodymium chloride solution concentration on the current efficiency of the electrolysis process were also investigated. The results show that the current efficiency reaches 92% when the neodymium chloride solution has an initial concentration of 0.3 mol/L, a current density of 250 mA/cm² and an electrolysis time of 60 min. The electrolysis product neodymium hydroxide is calcined to obtain neodymium oxide formed by agglomeration of a large number of rod-shaped crystals, and the median particle size of the particles is between 19.6 μm and 23.5 μm. This research provides a new idea for the preparation of neodymium oxide.