The invention discloses a method for preparing an alumina-based full-abrasive bonded abrasive tool. The method is carried out according to the following steps: taking a precursor of abrasive and adhesive by the mass percentage of 250:1, mixing and abrading the abrasive and the adhesive, performing press forming on the abrasive and the adhesive, and obtaining an alumina blank; presintering the alumina blank for 2 hours at a temperature of 1,100DEG C, cooling the alumina blank and obtaining a blank material; abrading and crushing the blank material, screening the blank through a screen cloth with 1,250 to 2,500 meshes, and obtaining alumina granules with the granule diameter of between 5 and 10mu m; taking the alumina granules, the adhesive and a pore-forming agent in mass ratio of 300:1.2:50, mixing and abrading the three compositions, performing press forming, and obtaining an blank to be sintered; and sintering the blank to be sintered without pressure, then cutting and forming the blank, and obtaining the alumina-based full-abrasive bonded abrasive tool. The method for preparing the alumina-based full-abrasive bonded abrasive tool can ensure the processing efficiency, improve the grinding efficiency and service life of the abrasive tool simultaneously, and realize the high-efficiency precise and super precise processing.