Abstract: The γ-Al₂O₃ modified with CoAl₂O₄ by the impregnation method was used as support to prepare cobalt catalysts. The physicochemical properties of the prepared catalysts were characterized with BET, XRD, H₂-TPR and XPS techniques and H₂-chemisorption experiment. The catalytic properties of the prepared catalysts were investigated for Fischer-Tropsch synthesis. It was shown that CoAl₂O₄ existed on the surface of γ-Al₂O₃, and thus, effectively weakening the interaction of Co and Al₂O₃ and resulting in a great increase in the reduction degree and the catalytic activity. The sample with a CoAl₂O₄ content of 20% shows the highest catalytic activity. It is worth noting that the CoAl₂O₄ modification decreased the CH₄ selectivity but enhanced the C₅₊ selectivity and catalytic stability.