The effect of temperature on electric fatigue of PLZT ferroelectric ceramics were studied in this paper. The research results show that the effect of temperature on electric fatigue behaviour of PLZT is significant, the higher the temperature is, the slower the fatigue velocity. The results of temperature dependence of the dielectric constant and microstructure observation by SEM shows that fatigue mechanism was mainly domain wall pining and intergranular microcracking initated by the internal stress concentration.