Ce3+-doped alkaline earth thiogallates with blue emission have been intensively investigated to fabricate full-color thin film electroluminescence (TEEL) devices, with sputtering, atom layer epitaxy (ALE) and molecular beam epitaxy (MBE) being the methods used. In this paper, a new way of preparing CaGa2S4:Ce TFEL devices, based on inter-layer reaction is first reported. CaS:Ce and Ga2S3 were deposited by electron beam evaporation, layer by layer, and CaGa2S4:Ce thin film was formed by post processing. The results of X-ray diffraction, scanning transmission electron microscopy (STEM) microphotographs and energy dispersive X-ray spectroscopy (EDX) show that CaGa2S4:Ce thin film with good crystallinity and stoichiometry were obtained. Photoluminescence (PL) and electroluminescence (EL) of these devices were investigated.