Abstract: Onestep synthesis of dimethyl ether (DME) from H2/CO was studied in a fixed bed reactor over hybrid catalyst CuOZnOAl2O3/γAl2O3HZSM5. The physicalchemical properties of the catalysts were also studied by means of H2TPR, XRD, TPO and N2O chemisorption. The results showed that in the process of catalyst deactivation, surface area of metallic Cu decreased greatly, but kept nearly constant TOF and selectivity to DME. Temperatureprogrammed oxidation (TPO) of the deactivated catalysts did not show significant O2 consumption, indicating that the deactivation was mainly caused by the sintering and conglomeration of Cu particles rather than carbon deposition or acidity loss. It was found that lower temperature, and N2/H2/CO/CO2 as feed gas could inhibit sintering deactivation. According to the experiment of the catalyst regenerated by means of redox cycle, Cu crystalline was redispersed and more than 75% activity was restored.