With the rapid development of the society, ceramic materials are being studied more and more. Recently, most of the studies on co-doping TiO2 ceramics are about trivalent acceptor and pentavalent elements which exhibit good dielectric properties, while the studies on divalent elements are relatively few. However, the mechanism, preparation process and the effects of different doped ion combinations on the dielectric properties are still unclear. Further research on the microstructure, dielectric properties and mechanism of co-doped TiO2 ceramics is of great significance. In this work, (Ca, Ta) co-doped TiO2 ceramics were prepared by a solid state reaction process. The effects of different components on their morphology, crystal structure and dielectric properties were studied. The sample with high viscosity needs to be sintered at 1400℃ for a minimum of about 4 h. When (Ca1/3Ta2/3)xTi1?xO2 ceramic with x≥7%, the second phase appeared in the (Ca1/3Ta2/3)xTi1?xO2 ceramic sample. Compared with pure TiO2, (Ca1/3Ta2/3)xTi1?xO2 ceramics all had giant dielectric constant, which roughly increased by two orders of magnitude. With the continuous increase of doping, the dielectric constant increased first and then decreased, while the dielectric loss was completely opposite. (Ca1/3Ta2/3)xTi1?xO2 ceramic with x=3% showed better dielectric and pressure-sensitive properties of ceramics. Ta doping led to the generation of electrons in the material, but Ca doping can produce vacancy and the defective dipole cluster can improve the dielectric performance.