Abstract: Stream reforming ethanol can not only produce hydrogen on board and solve the problem of storage,but also realize the mixed combustion of fuel with hydrogen-rich reformed gas and improve engine emissions.To get the optimal experiment method,the experiment was performed on a self-designed apparatus that could provide the similar temperature as the engine exhaust gas.The effects of reaction temperature,water/ethanol molar ratio and gas hourly space velocity(GHSV) on hydrogen concentration in the outlet gases were experimentally investigated over Cu₄₉Zn₂₁Al₁₈Zr₁₂ and Pt/CZO/Al₂O₃ catalyst.Results show that hydrogen productivity through steam reforming of ethanol over Pt/CZO/Al₂O₃ catalyst is higher than Cu₄₉Zn₂₁Al₁₈Zr₁₂ catalyst,especially when the reaction temperature is up to 823 K.The average values of hydrogen concentration are 40.26% and 47.78% when the reaction temperature ranges from 723 K to 973 K,GHSV is 720 h^-1,water/ethanol molar ratio are 6∶1 and 4∶1,respectively.However,as the Cu₄₉Zn₂₁Al₁₈Zr₁₂ catalyst gains a relatively higher productivity over 873 K and lower cost than Pt/CZO/Al₂O₃ catalyst,steam reforming of ethanol over Cu₄₉Zn₂₁Al₁₈Zr₁₂ catalyst may become a promising and practical way for producing hydrogen on vehicles.