The invention relates to a prosthodontic material based on a nanometer zirconia and alumina composite ceramic, wherein the prosthodontic material is prepared from the following components by weight: 10-40 parts of alumina having a particle size of less than or equal to micrometer, 6-12 parts of alumina having a particle size of more than or equal to nanometer, 20-50 parts of zirconia having a particle size of more than or equal to nanometer, and 31-52 parts of a ceramic glass having a micro-pore size of more than or equal to nanometer. The preparation method comprises: mixing the components according to a certain ratio in the presence of a certain amount of a solvent or in the absence of a solvent, carrying out mixing ball milling or sand milling on the obtained mixture, carrying out centrifugal infiltration grouting to form a billet, and sintering the dried billet at a high temperature under a high pressure to obtain the prosthodontic material based on the nanometer zirconia and alumina composite ceramic.