Mechanical properties including biaxial flexural strength, hardness, fracture toughness, as well as aging properties of zirconia ceramics with different content of yttria(3 mol% and 5 mol%) were investigated. Phase composition was calculated based on X-ray diffraction. Surface topography was analyzed via scanning electron microscopy. Thus we could analyze Y_2O_3's effect on mechanical and aging properties of zirconia ceramics. The result shows that the mechanical and aging properties of ZrO_2-3Y samples are...