The parent HZSM-5 was modified with a series content of ZnO via the incipient impregnation method by using Zn(NO₃)₂·6H₂O as a precursor. And the ZnO-modified HZSM-5 physically mixed with a commercial Cu/ZnO/Al₂O₃ was investigated as a bifunctional catalyst for steam reforming of dimethyl ether (DME). The samples were systematically characterized by XRD, FT-IR, N₂ adsorption–desorption at low temperature, and NH₃-TPD techniques. It was found that the introduction of ZnO would slightly influence the structure and crystallinity of the parent HZSM-5. Furthermore, the type (Lewis and Brønsted acid) and distribution (strong and weak acid sites) of acid could be adjusted by altering the content of ZnO, which took responsible for the DME conversion, H₂ yield, and selectivity of the carbon-containing products. As a result, an efficient catalyst for steam reforming of DME was obtained by adjusting the content of ZnO.