The invention relates to a shell catalyst used for preparing naphtha and diesel oil, which takes active carbon loaded with 5-35 percent of active component and 0.01-5 percent of auxiliary components by weight as a carrier; wherein, the active component is cobalt and the auxiliary components can be one or a plurality of La, Ce, Zr, Cr, Ti, V, B, Mn, Re, K, Pt, Ru, Mg, Ba and Ca. The preparation method of the catalyst comprises: a) preparing the solution containing soluble compounds of the loaded component; b) spraying the solution prepared in the step a) on the rolling carrier; c) drying or roasting the catalyst prepared in the step b) in inert gases. The invention can easily prepare eggshell type catalyst, which has the advantages of simple operation, uniform shell, easily controlled preparation process and good repeatability, thus being easy for large-scale production. Furthermore, the obtained catalyst has great service effect in overcoming the diffusion control problem in the chemical conversion process.