We have developed a perovskite thin-film electroluminescent device, opening up a new optical application of perovskite materials. Complete epitaxial growth of all of the layers and very flat interfaces with monoatomic steps have been obtained. With increasing driving voltage, the intensity of electroluminescence dramatically increases. The sharp electroluminescence peak at around 610 nm with 12 V becomes much stronger with increasing AC voltage. High-quality red light is emitted and the working voltage for whole-surface electroluminescence is as low as 10 V.