Combination of pyrolysis and vacuum ultraviolet (VUV) photolysis under reduced pressure offered an effective method to prepare yttria-stabilized zirconia (YSZ) thin films from metallo-oganic precursors at moderate temperatures. It became clear from IR and XPS analyses that thermal decomposition of metalloorganic precursors was accelerated by VUV excitation. The precursors dip-coated on a fused quartz substrate were found to decompose and crystallize into YSZ thin films as low as 603 K by thermal decomposition assisted by VUV irradiation. Without the VUV irradiation, however, the films were in an amorphous state at this temperature. It was also found that the VUV irradiation was more effective under air flow than under nitrogen flow, which suggests that active oxygen in the gas-phase generated by the VUV irradiation has an important role in the decomposition of the precursors.