Abstract: Nd-Co₃O₄ catalysts were prepared by hydrothermal and co-precipitation methods to catalyze the decomposition of N₂O. The catalysts prepared by hydrothermal method showed higher activity. Among the hydrothermal Nd-Co₃O₄ catalysts, the catalyst with Nd/Co molar ratio of 0.01 had higher activity. 0.01Nd-Co₃O₄ catalyst was then impregnated by K₂CO₃ solution to prepare K-modified catalyst. The catalysts were characterized by means of X-ray diffraction (XRD), nitrogen physisorption, scanning electrons microscopy (SEM), X-ray photoelectron spectroscopy (XPS), hydrogen temperature-programmed reduction (H₂-TPR), and oxygen temperature-programmed desorption (O₂-TPD). The results show that Nd-Co₃O₄ and K-modified catalysts exhibit spinel structure. In contrast to bare Nd-Co₃O₄, the K-modified catalyst with higher activity is due to its weaker strength of Co-O bond and easier desorption of surface oxygen species. In addition, over 90% conversion of N₂O can be reached over 0.02K/0.01Nd-Co₃O₄ at 350 ℃ for 40 h under the co-presence of oxygen and steam in feed gases.