Abstract: YSZ electrolyte thin films were prepared by tape casting from nanocrystalline powder. The properties of YSZ nanocrystalline powder, adobe by tape casting and sintered thin films were analyzed. The YSZ nanocrystalline powder has a narrow size distribution of 0.1-0.2 μm and the median size is 0.157 μm. The beginning shrinkage temperature of the YSZ nano-powder is 968.9℃ from its sintering curve. The highest shrinkage rate appears at 1279.9℃, and by 1400℃ the shrinkage rate is stable, almost up to 20%. The adobe by tape casting has high density and its relative density is up to 64.1%. The relative density of the sintered YSZ thin films is 97.8%. The grain size of YSZ is in the range of 1-4 μm, which show uniform with the microstructure by SEM, as well as grain boundaries are obvious. The YSZ thin films show good electrical properties with increasing temperature and their conductivity is 0.106 S/cm at 900℃.