The invention discloses a method for preparing a demetalation catalyst carrier. The method comprises the following steps: 1) extracting deactivated hydrodemetalation catalyst, roasting the deactivated hydrodemetalation catalyst, and screening the deactivated hydrodemetalation catalyst, wherein the roasting temperature is 500-600 DEG C, and the roasting time is 5-10 h; 2) employing an organic acid solution for performing saturated impregnation on the catalyst, filtering the dipped catalyst, and drying the catalyst; 3) performing water vapor processing on the dried catalyst; and 4) drying the catalyst after water vapor processing, performing high temperature roasting and purging, employing rapid condensation on the gas to recover the metal, and taking the residual solid as an alumina carrier of the demetalation catalyst. The method can reuse the carrier of the deactivated hydrodemetalation catalyst and active metal.