The invention discloses a mixed oxide catalyst for preparing highalcohol with synthesis gas. The catalyst comprises, by weight, 1-99% of a Co-based catalyst A and 99-1% of a Cu-based catalyst B. The catalyst is high in activity, total alcohol selectivity and C<2+> and C<6+> alcohol selectivity, good in stability and long in service life, the operation temperature can be maintained at 180-350 DEG C, and reaction pressure is 0.1-10 MPa. Due to the fact that catalyst preparation method of the catalyst is simple and easy to repeat, the catalyst has potential industrial application prospect.