Abstract: With screen-printing technique, a ceramic thick film substrate was fabricated by printing and sintering Ag/Pt alloy internal electrodes and high dielectric constant ceramic thick film insulating layer on Al 2O 3 ceramic substrate. Thereby a novel thick dielectric electro-luminescent (TDEL) device was prepared by using the ceramic thick film substrate. The whole structure of the device is ceramic substrate/internal electrodes/thick dielectric film/light-emitting layer/thin dielectric film/ITO. The threshold voltage and the dependence of brightness on voltage and frequency were measured, respectively. The decay characteristic of the device was also analyzed. Result shows that a thick film electroluminescent device has lower threshold voltage and less dielectric wastage than a thin film electroluminescent device. A TDEL device avoids cross phenomenon effectively.