A method for preparing hydrorefining catalyst comprises the following steps: (1) mixing an aqueous ammonia solution with a polyamine complexing agent to form a mixed solvent; (2) adding a cobalt salt to the mixed solvent, dissolving the cobalt salt, and then adding a molybdenum salt and optional salts of other active components, and dissolving them to prepare an impregnating solution; and (3) impregnating a support with the impregnating solution, followed by aging, drying, and activating the impregnated support to form a hydrorefining catalyst. The hydrorefining catalyst prepared by this method has good activity, selectivity and stability in use.