Scandium and Yttrium co-doped ZrO2 (4Sc4YSZ) thin film solid electrolyte has exhibited improved conductivities and phase stability by considering advantages of both Y-doped zirconia (YSZ) and Sc-doped zirconia (ScSZ). In this study, a solid electrolyte thin film of 4Sc4YSZ deposited on a new LSM-4Sc4YSZ composite electrode was conducted. To obtain a dense electrolyte, the effect of pre-sintering temperature of the LSM-4Sc4YSZ electrode substrate in the deposition of the 4Sc4YSZ thin film was investigated. X-ray diffraction (XRD) analysis revealed distinct phases of rhombohedral peaks for LSM and cubic peaks for the composite 4Sc4YSZ component and deposited thin film electrolytes. It was observed from the morphological results via scanning electron microscopy (SEM) that pre-sintering of the electrode substrate affects the densification of the deposited solid electrolyte. A dense 4Sc4YSZ thin film electrolyte was obtained by pre-sintering the LSM-4Sc4YSZ electrode at 1300°C than those deposited on the substrates with lower pre-sintering temperatures.