In this study, barium zirconate powder was prepared by a solid-state reaction using different barium and zirconium sources. Thermal analysis and phase identification demonstrated that barium zirconate could be synthesized from barium hydroxide at a lower temperature than from barium carbonate. Copper oxide was used as a dopant to improve the sintering performance of the barium zirconate; sintered samples with 2 mol% copper oxide exhibited relatively superior comprehensive performance. The mechanical properties and thermal stability of barium zirconate were characterized; the internal composition structure of the samples prepared with basic zirconium carbonate was uneven, resulting in somewhat reduced performance. The samples maintained a high elastic modulus and strength before and after thermal shock. It was observed under an electron microscope that a liquid phase was generated inside the samples after thermal shock, and numerous barium zirconate whiskers were formed. The whiskers ensured that the sample could withstand greater thermal stress, thus exhibiting excellent thermal shock stability. This work demonstrates the promising potential of barium zirconate in the field of high-temperature materials.