In this article, one cast technique to fabricate 20-40 wt %AgNO3-doped polyvinyl alcohol (PVA) composite films of which electrical resistance sharply dropped (4-5 order) in a certain temperature range was reported. The phase, structure thermal, and electrical resistivity properties of films at different heat treatment temperatures were studied by X-ray diffraction (XRD), scanning electrical microscopy (SEM) and differential scanning calorimetry (DSC). The results showed that all the AgNO3 (20-40 wt %) doped PVA films presented an exothermic peak at 182 degrees C. And the temperature of exothermic peak kept constant for various contents of AgNO3. Meanwhile, the phase composition of the films was greatly affected by the heat treatment temperature. Ag particles were generated during the heat treatment process, and the content of Ag particles increased with increasing the temperature. The resistivity of PVA/AgNO3 films decreased with increasing the temperature. And a sharp decrease appeared at 155-165 degrees C due to the generation and contact of a mass of Ag particles at this temperature. The thermal-electrical results suggested the applicability of these materials in temperature sensor, for example, critical temperature resistor thermistor. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 122: 813-818, 2011