Carbon dioxide (CO2) hydrogenation is an alternative catalytic reaction for the conversion of CO2 into methanol and dimethyl ether (DME). Alumina is widely used as a catalyst in CO2 hydrogenation. Drying of the porous support is an effective process, which can directly affect the structural characteristics and performance of the catalyst. This work investigated the effect of microwave drying on the properties of an alumina support and a Cu/Al2O3 catalyst. Microwave drying of the support at 600 and 1000 W shortened the drying time by 86 and 92%, respectively, compared to hot air drying at 100 °C. Microwave drying could enhance the distribution of the alumina particles, resulting in a larger surface area and pore volume of the support. In contrast, hot air drying caused alumina particle aggregation that led to a small surface area and pore volume of the support. The Cu/Al2O3 catalyst, for which the support was microwave-dried at 1000 W (Cu/Al2O3-MW1000), had the greatest copper distribution, BET surface area (229.5 m2/g), pore volume (0.39 m3/g) and strong acidic site (1.25 mmol NH3/g Cu). These characteristics of catalyst led to the presenting of the highest CO2 conversion, DME selectivity, and DME space time yield during CO2 hydrogenation. A catalyst utilizing the support prepared by microwave drying at 1000 W exhibited the highest average CO2 conversion, DME selectivity and space time yield of DME of 30.67%, 9.99% and 156.5 gDME/kgcat h, respectively at a reaction temperature of 260 °C for 4 h. In addition, the stability of Cu/Al2O3-MW1000 catalyst was excellent over a 24 h reaction period.