Al2O3/ZrO2 composites have been investigated as the bio-inert material. In the present work Al2O3/ZrO2 Micro/Nano composites were prepared by colloidal method. The effects of the concentration of zirconium propoxide and the sintering temperature were studied on the distribution of ZrO2 nano-grains in Al2O3 matrix and mechanical properties of composites. XRD patterns for all compositions showed a single phase of a-Al2O3, and the tetragonal and monoclinic ZrO2 phases. Samples sintered at 1650°C demonstrated the high bulk density with value of 86-92% of theoretical density. ZrO2 nano-grains were dispersed within Al2O3 grain and the grain boundary. The sample of the highest flexural strength of 710 MPa was synthesized using 100% Zr propoxide solution and sintered at 1650° C. The flexural strength was found to increase with increasing the concentration of Zr propoxide and sintering temperature.