The invention discloses a preparation method of a boron-containing hydrogenation and demetalization catalyst. The preparation method comprises steps as follows: (1) hydrogenation active components, namely, an impregnation liquid I and a boron-containing solution I are used for impregnating a physical pore expanding agent I respectively, hydrogenation active components, namely, an impregnation liquid II and a boron-containing solution II are used for impregnating a physical pore expanding agent II respectively, and the impregnated physical pore expanding agent I and the impregnated physical pore expanding agent II are dried and soaked with a urea solution respectively for standby use; (2) the physical pore expanding agent I and the physical pore expanding agent I obtained in the step (1) are mixed with pseudo-boehmite dry gelatine powder, a chemical pore expanding agent, an extrusion aid and a peptizing agent, the mixture is kneaded to form a plastic body, the plastic body is extruded to form strips, formed products are put in a sealing device for heat treatment, a treated material is dried and calcined, and a modified alumina support is prepared; (3) a hydrogenation active component, namely, an impregnation liquid III is used for impregnating the modified alumina support, the catalyst is dried and calcined after impregnation, and the boron-containing hydrogenation and demetalization catalyst is prepared. According to the catalyst prepared with the method, the content of active metal is relatively high at large pores and relatively low at small pores, the utilization rate of the large pores is remarkably increased, and the hydrogenation and demetalization catalyst has high activity and long-period operation stability.