Cu-Mn-Al spinel solid solution catalysts were prepared by coprecipitation method using copper nitrate, aluminum nitrate and manganese nitrate, and tested in methanol steam reforming reaction for the preparation of hydrogen. The catalysts were characterized by BET, H2-TPR, XRD, SEM, XPS, etc. The effects of Mn ratio (CuMnxAl4-x , x = 0 ~ 0.5) were investigated on catalyst physicochemical properties, morphology, as well as the catalytic performance. The results showed that the specific surface area, reduction properties and surface chemistry of catalyst samples were altered with Mn ratio. With Mn ratio x rising of from 0 to 0.5 (based on the amount of copper), the specific surface area decreased, the size of spinel particles increased, and became more difficult to reduce. The best performance was found for the catalyst CuMn0.25Al3.75, where under the reaction conditions of 260 ℃, 0.3 MPa, n(H2O)∶n(CH3OH) =1∶1, weight hourly space velocity(WHSV) 3.0g-feed/g-cat/h, the highest methanol conversion attained 91.7% and dropped to 78.7% after 150h running, which are substantially higher than the CuAl spinel catalyst contains no Mn.