A series of SnOx-Sb2O3 thin film varistors were fabricated through hot-dipping tin oxide films deposited by radio-frequency magnetron sputtering in Sb2O3 powder at varied temperatures in air. With the increase in hot-dipping temperature (HDT) from 200 degrees C to 600 degrees C, the nonlinear coefficient () of the samples increased first and then decreased, reaching the maximum at 500 degrees C, which was mainly determined by the completeness of high-resistant Sb2O3 layer at tin oxide grain boundary and the chemical composition of tin oxide films. Correspondingly, the leakage current (I-L) decreased first and increased later. The breakdown electric field (E-100mA) decreased constantly with increasing HDT. The SnOx-Sb2O3 film varistors prepared at 500 degrees C exhibited the optimum nonlinear properties with the maximum of 10.88, the minimum I-L of 36.3mA/cm(2), and an E-100mA of 0.0188V/nm. The obtained nanoscaled film varistors would be promising in electrical/electronic devices working in low voltage.