Abstract: CuO/ZnO/Y2O3 was prepared by deposition-precipitation method and was mechanically mixed with γ-Al2O3 to prepare CuO/ZnO/Y2O3/γ-Al2O3 bi-functional catalysts for dimethyl ether steam reforming (DME SR). The results indicated that CuO/ZnO/Y2O3/γ-Al2O3 bi-functional catalyst showed superior performance to the conventional CuO/ZnO/Al2O3/γ-Al2O3 bi-functional catalysts. Differences in surface acidity and microstructure between the two bi-functional catalysts are discussedwith reference to Brunauer-Emmett-Teller (BET), N2Ochemisorption, NH3 temperature-programmed desorption (NH3-TPD), X-ray diffraction (XRD) and H2 temperature-programmed reduction (H2-TPR) analyses. The results showed that CuO/ZnO/Y2O3/γ-Al2O3 had better copper dispersion on its surface and smaller copper crystallites than CuO/ZnO/Al2O3/γ-Al2O3 did. Additionally, Y2O3 has better thermal stability than Al2O3, which may prevent copper crystallites from conglomeration. The performance of the reforming component and the catalytic activity as well as stability of the bi-functional catalyst was thus improved.