High entropy ceramic is a kind of ceramic developed based on the high entropy alloy in recent years. The appearance of high entropy ceramics provides a new concept and route for developing non-metallic materials with excellent properties. In present work, a series of high-entropy ceramics with a molar ratio of A site—(La_0.2Li_0.2Ba_0.2Sr_0.2Ca_0.2)TiO₃ were successfully synthesized by solid state reaction. The effects of sintering temperature on phase, microstructure and electric properties were investigated. Results show that the high-entropy ceramics sintered at current temperatures are of cubic perovskite structure, and exhibit excellent insulation, with low leakage current density of J value around 10^-8-10^-6 A/cm². Although the grain size increases with the increase of sintering temperature, the correlation between microstructure and dielectric properties of (La_0.2Li_0.2Ba_0.2Sr_0.2Ca_0.2)TiO₃ ceramics is not significant. The dielectric constant reaches its maximum value at 1350 ℃, with the value of 230 at the frequency of 100 Hz. Meanwhile, this high-entropy ceramic has relaxation behavior, and the relaxation peak of the permittivity moves towards high temperature with the increase of frequency.