The invention discloses a method for preparing mesoporous alumina ceramics with high specific surface areas. Aluminum dihydrogen phosphate is used as a binder, and the mesoporous alumina ceramics are prepared by the aid of powder sintering processes. The mesoporous alumina ceramics are mainly made of nano-boehmite, and the aluminum dihydrogen phosphate is used as the binder. The method includes forming powder by the aid of sheet pressing processes, sintering the powder at low temperatures to synthesize the mesoporous alumina ceramics. The method has the advantages that nano-particles are piled, so that pore passages of the mesoporous alumina ceramics can be constructed; the powder can be formed by the aid of the sheet pressing processes, so that the mesoporous alumina ceramics in required shapes can be prepared according to actual requirements; the powder is sintered at the low temperatures, accordingly, energy can be saved, preparation techniques can be simplified, the production cycle can be shortened by a half, and the mesoporous alumina ceramics can be efficiently produced on a large scale.