The invention discloses a graded directional preparation method for a deasphalted oil hydrodemetallization catalyst. The method includes steps: a, repeatedly adding acid solution and alkaline solution, adopting an in-situ repeated hydrolysis-deposition method to finally adjust a final pH value of a reaction system to 7-10, and performing aging, washing and drying to obtain an aluminum oxide precursor with large-diameter main reaction holes; b, mixing the aluminum oxide precursor at the step a with a pore enlarging agent, a peptizing agent and an extrusion aid to obtain plastic by kneading, and performing extruding, drying and calcining to prepare an aluminum oxide carrier with main reaction holes and main diffusion holes; c, adopting an equivalent-volume impregnation method for loading group VIII and group VIB reactive metal components to the aluminum oxide carrier, airing, drying and calcining to obtain the deasphalted oil hydrodemetallization catalyst.