Highly dispersive hydrotalcite-like composite metal oxides were prepared by coprecipitation method. CO₂-TPD characterization showed that the adsorption capacity over the samples at low (<300ºC) and middle (300~550ºC) temperatures was improved by using La or Cu to modify the sample of MgAlO, while slightly reduced at high temperature (>550ºC). The experimental results showed that the composite metal oxide, Me_xO_y (Me=La, Mg, Al), had relatively good performance on N₂O decomposition. A series of Ru/Me_xO_y catalysts were prepared by programed impregnation method. CO₂-TPD analysis indicated that the samples of Ru/Me_xO_y not only increased the total CO₂ adsorption capacity, but also obviously enhanced CO₂ adsorption capacity at 300~550ºC compared with Me_xO_y. TEM characterization showed that the Ru component was uniformly loaded on the support surface under nanoscale. N₂O catalytic decomposition showed that the suitable Ru loading on support was 2.0(wt.)%, i.e., Ru(2.0)/Me_xO_y. Under conditions of (v/v) 10% N₂O+82% N2+5.0% O₂+3.0% H2O, 30000h^-1 of space velocity, 510ºC, the stability test showed that N₂O conversion remained ca. 95.0%, indicating that Ru(2.0)/Me_xO_y had good stability and activity at relatively low temperature.