To improve mechanical properties of TiO₂-added zirconia-toughened alumina (ZTA), the microstructure and sinterability of ZTA composites fabricated from ZTA powders containing (Zr, Ti)O₂ and sintered in an atmosphere of N₂+5%H₂ were investigated. In the sintered ZTA, the concentration of Ti in grains of Al₂O₃ or (Zr, Ti)O₂, was analyzed with EDS attached to an AEM apparatus. Experimental results indicated that some Ti ions diffused to the grain boundary and into Al₂O₃ grains, thereby enhancing the densification of ZTA powders sintered in N₂+5%H₂, the grain growth is less than that of powders sintered in air. The solubility of TiO₂ in (Zr, Ti)O₂ in ZTA sintered in N₂+5%H₂ was smaller than that of ZTA sintered in air, which diminished the tetragonal zirconia phase in the ZTA sintered body.