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LiTaO 3 /Al 2 O 3 ceramic composites were fabricated by hot pressing and pressureless sintering, respectively, to investigate the effect of piezoelectric secondary phase on the properties of structural ceramics. Phase constitution, microstructure and mechanical properties of the ceramic composites were studied. LiTaO 3 could stably coexist with Al 2 O 3 during sintering. LiTaO 3 phase was located at the grain boundaries of Al 2 O 3 matrix fabricated by different processing routes. Domain structures were clearly seen in LiTaO 3 , confirming that LiTaO 3 remained hexagonal ferroelectric phase. About 5 vol.%LiTaO 3 /Al 2 O 3 ceramic composite prepared by pressureless sintering at 1300 °C showed an increase in fracture toughness. Energy dissipation due to domain switching was suggested as a toughening mechanism. With the increasing of LiTaO 3 content, the domain switching toughening mechanism was decompensated by the decreased relative density of LiTaO 3 /Al 2 O 3 ceramic composites. For LiTaO 3 /Al 2 O 3 ceramic composites prepared by hot pressing at 1500 °C, the bending strength decreased because of the increased grain size of Al 2 O 3 matrix. The toughening effect due to domain switching was also decompensated by the coarsening of Al 2 O 3 matrix grains, the weaker net-like LiTaO 3 phase and the weaker bonding strength between LiTaO 3 phase and Al 2 O 3 matrix.