Abstract: The simulated radionuclide neodymium was separated from high-level liquid waste using in-situ hydrotalcite synthesis. The optimum conditions of removal of neodymium were determined by the single factor test, acid-base titration and XRD analysis. The structure and morphology of Nd-containing hydrotalcite were analysed by FT-IR, SEM and TEM. The results showed that the optimum conditions of separation were initial Nd3+ concentration below 150 mg/L, pH equal to 10 and Mg/(Al+Nd) molar ratio equal to 3. Under these conditions, the neodymium removal rate was 96.40% by the parallel test. Nd was embedded into the crystal lattice of hydrotalcite, and the main morphology of the Nd-containing hydrotalcite was a layered hexagonal shape. The major calcined product of Nd-containing hydrotalcite was spinel. Nd₂O3 was not observed, which indicated that after calcination, the Nd embedded into the crystal lattice of hydrotalcite still existed in the spinel structure.