The catalytic decomposition of N2O was investigated over a series of CuO-CeO2 mixed oxide catalysts prepared by the hydrothermal method. It was found that CuO-CeO2 mixed oxide catalyst exhibited higher activity than pure CuO and CeO2. The co-existence of CuO and CeO2 exhibited a synergetic effect, which inhibited the crystallization of the CuO phase, leading to the high surface area. Moreover, the two redox couples (Ce4+/Ce3+ and Cu2+/Cu+) formed over CuO-CeO2 mixed oxide contribute to the desorption of surface adsorbed oxygen species and thus the regeneration the active sites, which is favorable for the catalytic N2O decomposition to proceed.