Lanthanide-doped lead zirconate titanate (PLZT) transparent ceramics have significant potential for application in modern optical communication and high energy laser technology due to their exceptional optical transparency and electro-optical effects. However, the electro-optical (E-O) properties of PLZT transparent ceramics are highly sensitive to changes of ambient temperature, which presents a significant challenge in their application in E-O modulators across a wide temperature range. The objective of this study was to investigate the effects of temperature on the ferroelectric, dielectric and E-O properties of PLZT (10/65/35) transparent ceramics, and optimize the material E-O properties and their temperature stability by regulating the distribution of the key doping element La³⁺ in micro regions. A series of PLZT ceramic samples with pure perovskite structures were obtained by a conventional hot-press sintering process in oxygen atmosphere. The resulting microstructures are uniform and dense, and the optical transmittances of the samples are 52%~60% at a wavelength of 632.8 nm. The broadened dielectric peaks of PLZT ceramics indicate the relaxation characteristics of the materials, and it is promoted as La³⁺ content increasing, and enhance obviously by the enlarged La³⁺ fluctuation in micro-regions in the 0-3 and 2-2 composite PLZT ceramics with a more broadened dielectric peak and higher dielectric constant. The ferroelectric hysteresis loops (P-E) of the PLZT ceramics all exhibit a gradual decrease in maximum polarization value (P_max), residual polarization value (P_r), and coercivity field strength (E_c) with the temperature increasing. P_max values of 0-3 and 2-2 composite PLZT (10/65/35) ceramics are obviously higher than that of the well-distributed PLZT (10/65/35) ceramics, and their equivalent secondary E-O coefficients are significantly increased near the temperature of diffuse phase transition.