Abstract: A series of ZrO2-Al2O3 mixed oxides with different ZrO2 contents were prepared using ZrOCl2·6H2O and AlCl3 as the raw material by means of co-precipitation method. The Co/ZrO2-Al2O3 catalysts with 12% cobalt loading were prepared using the incipient wetness impregnation method. XRD, NH3-TPD, TPR and in situ IR characterization results show that surface areas of the mixed oxides support are first increased and then decrease with the increase of the ZrO2 content in the mixed oxides. The average pore size of the mixed oxides is smaller than that of the single ZrO2 or Al2O3 oxides. When the mixed oxides were used as the support of the cobalt-based catalyst, the mixture of zirconia and alumina can result in the increase of the surface area and support acidity. Meanwhile, a new crystal phase could also be formed due to the interaction between alumina and zirconia. When the ZrO2-Al2O3 mixed oxides were used as the supports of the cobalt-based catalysts, the dispersion of metallic cobalt and the amount of adsorbed CO species on the surface of the catalysts are reduced and the reduction behaviors of cobalt oxides are changed. In the test of the F-T reaction, CO hydrogenation demonstrated that cobalt supported on ZrO2-Al2O3 mixed oxides have lower catalytic activity and C5+ selectivity compared with the cobalt supported on the single alumina or zirconia catalysts.