Zirconia-toughnened alumina(ZTA) powders that were uniformly coated with zirconia and yttria on the surface of alumina particles were prepared in order to inhibit the grain growth of alumina. Alumina particles were ultrasonically dispersed in the ethanol solution of Zr-n-propoxide, and then the Zr-alkoxide was hydrolyzed. Hydrated zironia as thin film was stabilized to tetragonal crystalline form by doping yttria as a stabilizer. The prepared ZTA powders had the good sinterability even at the lower temperature. As a result, the sintered bodies showed the enhanced fracture toughness compared with pure alumina. The relative density and fracture toughness(KIC) of the ZTA bodies sintered at 1550$^{circ}C$ were 98% and 5 MPa$.$m1/2 respectively.