Based on the knowledge of the mechanisms of methanol synthesis and methanol dehydration, it was predicted that if the dispersion of CuO/ZnO/γ-Al 2 O 3 in hybrid catalysts for direct synthesis of dimethyl ether from synthesis gas was enhanced, the formation rate of dimethyl ether would be increased. In order to justify the prediction, five preparation methods, including two mechanical mixing ones and three co-precipitation ones were used to prepare the catalysts. It was found that co-precipitation impregnation and co-precipitation of Cu/Zn by NaAlO 2 provided the catalyst with the highest activity and co-precipitation of Cu/Zn/Al by Na 2 CO 3 resulted in the worst catalyst. Combined with the XRD results it is deduced that the active phases for direct synthesis of dimethyl ether from synthesis gas are highly-dispersed fine crystallites of CuO/ZnO/γ-Al 2 O 3 .Calcination temperature of the precursor of γ-alumina used in the methods of mechanical mixing was also studied. It was found that a calcination temperature of 550°C brought about the most active dehydration catalyst with the largest surface area and nearly pure γ-alumina of poor crystallinity. So it might be concluded that the active phase for methanol dehydration is fine crystallites of γ-alumina.