NiMgAlO catalysts were prepared by two methods: coprecipition and impregnation. They were used to simultaneously adsorb SO2 and NO with O2 in a fixed bed at atmospheric pressure. Typically the molar composition of the feed gas was 1% SO2, 0.2% NO and O2 with ultra-high purity Ar as the diluent. The results showed the catalysts were excellent materials for the simultaneous oxidation adsorption of SO2 and NOx. The two kinds of catalysts were compared for the SO2 and NOx adsorption capacity. The NiMgAlO catalyst prepared by coprecipition had better adsorption than impregnation. When NiMgAlO catalysts with 10 wt-% Ni content were calcined at 550°C, adsorption capacity was the largest at 120°C adsorption temperature: 1.392 mmol SO2 and 0.213 mmol NOx were adsorbed on 1 g catalyst prepared by the coprecipition method. The causes are seen by the XRD, surface area and porous size analysis.