<p>Titanium oxide ceramics have very good application prospects in the field of thermoelectric conversion due to high thermal stability, environmental friendliness, and low cost. Titanium oxide ceramics exhibit a very high Seebeck coefficient, but their low electrical conductivity and high thermal conductivity lead to very low thermoelectric conversion efficiency. In this study, the thermoelectric properties of the materials were regulated by adding graphite during the sintering process. The results showed that the electrical conductivity increased significantly and the thermal conductivity decreased as the amount of graphite added was increased during the sintering process. When 2.0&#xa0;wt.% graphite was added during the sintering process, the power factor reached 442&#xa0;μWm⁻¹&#xa0;K⁻² at 973&#xa0;K, and the thermoelectric value (<i>ZT</i>) increased to 0.15. The synergistic optimization of thermoelectric properties could be achieved due to modulating oxygen defects and grain boundaries by adding graphite during the sintering process, which could make the carrier concentration increase and significant scattering to phonons enhanced at the same time.</p>