The invention discloses a method for preparing a zirconia-alumina composite oxide xerogel. An aluminum hydroxide sol and a zirconium-containing sol are prepared firstly, and then are mixed, aged, washed, filtrated and dried to obtain the composite oxide xerogel. In the method, most of zirconia is distributed on the surface of alumina, the impact on a pore structure of the alumina is weakened, the co-catalysis of the zirconia is improved, the advantages of the alumina and the zirconia are fully utilized, and the obtained composite oxide xerogel has the characteristics of large pore volume, high specific surface area, concentrated pore size distribution and controllable acidity, and is suitable for being used as a hydrogenation catalyst carrier.