The invention belongs to the technical field of oxide ceramics and in particular relates to a method for preparing a dark blue zirconia ceramic. The method comprises the following steps: by taking zirconium n-butoxide as a base material, yttrium acetate as a stabilizer, polyvinylpyrrolidone as a dispersing agent and an adhesive coating material, and absolute ethyl alcohol as a solvent, performing an ultrasonic reaction so as to obtain a sol solution wrapped by polyvinylpyrrolidone; by taking stearic acid as a dispersing agent and a medium, aluminum monoacetate and cobaltous acetate as raw materials, and ammonium hydroxide as a reaction agent and a pH adjusting agent, and an ethanol solution as a solvent, performing a sealing reaction so as to obtain clear pink sol; mixing the clear pink sol with a penetrant, putting into the sol solution wrapped by polyvinylpyrrolidone, and performing a sealed constant-pressure distillation reaction and a vacuum distillation reaction so as to obtain ceramic powder; and finally performing constant-temperature pressurizing sintering and gradient high-temperature sintering on the ceramic powder, thereby obtaining the dark blue zirconia ceramic. The method provided by the invention is simple and easy to operate, the obtained zirconia ceramic structure is dense and stable and uniform in coloring, and meanwhile has the mechanical properties of zirconium oxide.