The invention provides a Fischer-Tropsch synthesis cobalt-based catalyst and a preparation method of the Fischer-Tropsch synthesis cobalt-based catalyst. The catalyst contains a silicon aluminum boron composite oxide, cobalt and an assistant, wherein the assistant contains an oxide/oxides of one or two or more VB-group elements, and an oxide/oxides of one or two or more elements of Mn, Ti, Zr, Fe, W, Ce, La and Ni; according to the total amount of the catalyst, the content of cobalt is 1wt%-30wt%, the content of the oxide/oxides of the VB-group elements is 0.02wt%-9wt%, the content of the oxide/oxides of other assistants is 0.01wt%-6wt%, and the balance is the silicon aluminum boron composite oxide. The invention further provides the silicon aluminum boron composite oxide and a preparation method of the load cobalt catalyst. The catalyst is used for the Fischer-Tropsch synthesis reaction, the CO conversion rate and the C5+ selectivity are both higher than 80%, and the selectivity of kerosene and diesel fraction, namely C10-C20, in the C5+ is up to more than 50%.