The cobalt-imbedded zeolite catalysts in which Co3O4 particles were compatibly imbedded or confined into the zeolite crystals were prepared with the conventional Co/SiO2 catalyst as the precursor and the silica source by a hydrothermal synthesis method. The effect of hydrothermal condition on the catalyst properties and the catalytic performance for the direct synthesis of gasoline-range hydrocarbons was comparatively investigated in this work. And the formation mechanism for the synthesis of this kind of catalyst was proposed. The coincidence of the rate of the silica dissolving process and the zeolite crystallization process was proved to be the key to the rational design of this imbedment-structured catalyst. Compared with the conventional Co/SiO2 catalyst and the zeolite-supported catalyst, the optimized cobalt-imbedded zeolite catalysts present significantly higher gasoline selectivity and produce more iso-paraffins, which can be reasonably attributed to the confined reaction environment, the high diffusion efficiency, the proper reduction behavior, and the suitable acidic properties. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.