This study focuses on the effect of firing temperature on high-temperature electric ceramics, and reveals the effect of temperature on the densification of the material by comparing the mechanical properties and microstructure of the specimens at different firing temperatures (1240 °C–1320 °C). Revealed the change rule of shrinkage under different firing temperatures. During the sintering process of high temperature ceramics, shrinkage is a key parameter that directly affects the final size and properties of the material. Temperature is one of the main factors affecting shrinkage. As the sintering temperature increases, the diffusion rate between ceramic particles is accelerated and the densification process is accelerated, resulting in an increase in shrinkage. However, too high temperature may lead to excessive grain growth or defects, which may affect the mechanical properties and dimensional stability of the material. Therefore, optimizing the sintering temperature is essential to control the shrinkage of high-temperature ceramics. Studies have shown that in the appropriate temperature range, the shrinkage is positively correlated with the temperature, but beyond a certain critical temperature, the change of shrinkage tends to flatten or even abnormal. By precisely controlling the sintering temperature, the shrinkage behavior of high-temperature ceramics can be effectively regulated, so as to obtain ideal material properties.