Red emitting CaS:Eu,S electroluminescent(EL) device prepared at 550.deg. C by an electron-beam evaporation technique, demonstrated luminance of 175cd/m$^$2/ and efficiency of 0.311m/W with 3kHz drive. Luminance was increased with the increase of applied voltage and frequency. From the results of the PL spectrum and the EL spectrum, the CaS:Eu, S device showed emission peak near 640nm resulted from the transition of EU$^$2+/ 4f$^$6/5d.rarw.4f$^$7/. The capacitance of the phosphor layer from the Sawyer-Tower circuit was 10.5nF/cm$^$2/.