The invention discloses A-site high-entropy 
perovskite oxide MeTiO3 thermoelectric 
ceramic and a preparation method thereof. The A-site high-entropy 
perovskite oxide MeTiO3 has a single-phase 
perovskite structure, the elements in the A-site high-entropy perovskite 
oxide MeTiO3 are uniformly distributed without agglomeration, and the A-site high-entropy perovskite oxide MeTiO3 has thermoelectric performance and can be used in the field of 
thermoelectric materials. The 
chemical composition of the A-bit high-entropy perovskite oxide MeTiO3 is (Ca < 0.2 > Sr < 0.2 > Ba < 0.2 > La < 0.2 > Pb < 0.2 >) TiO3, (Ca < 0.25 > Sr < 0.25 > Ba < 0.25 > La < 0.25 >) TiO3, (Ca < 0.25 > Sr < 0.25 > Ba < 0.25 > Pb < 0.25 >) TiO3, (Ca < 0.25 > Sr < 0.25 > Ba < 0.25 > Nd < 0.25 >) TiO3, (Ca < 0.25 > Sr < 0.25 > Ba < 0.25 > Sm < 0.25 >) TiO3, and (Ca < 0.25 > Sr < 0.25 > Ba < 0.25 > Eu < 0.25 >) TiO3. According to the invention, the high entropy of the 
perovskite structure is realized, the disorder degree of atom arrangement in the material composition is improved, the 
phonon scattering is increased, and the 
thermal conductivity is reduced, so that the thermoelectric performance is improved. In the 
sintering process, 
oxygen atoms are migrated and discharged through 
oxygen vacancies in material 
crystal lattices, the 
porosity is reduced, the 
ceramic density is improved, meanwhile, the 
oxygen vacancy concentration is improved, and the carrier concentration of the material is improved. By adopting a reduction annealing process of 
argon and carbon 
powder, the 
semiconduction of perovskite oxide is realized, the carrier concentration of the 
ceramic is improved, the 
conductivity is improved, and the thermoelectric performance is further improved.