A series of Cs promoted copper oxide catalysts were prepared by co-precipitation method and tested for the direct decomposition of nitrous oxide (N2O). The Cs promoted catalysts were more active particularly with a molar ratio of Cs/Cu at 0.1 compared to bulk CuO. Methods of XRD, BET, XPS, H-2-TPR, and N2O-TPD were used to characterize these catalysts to evaluate structure activity relationship. The characterization results indicated that the addition of Cs could improve the reduction of Cu2+-Cu-0 by facilitating the desorption of adsorbed oxygen species, during the N2O decomposition. The influences of oxygen and steam on N2O decomposition over these catalysts were also studied.