PdO/TiO2 nanocomposites were prepared by ployol method. TEM, XPS and FSEM were used to observe and measure the microstructure and chemical state of the PdO/TiO2 film. In this process, Pd(acac)2 was a Pd precursor , ethylene glycol was a reductant, and nano TiO2 powder (Degussa P25) was a support, in which the nanopaticles of Pd were highly dispersed on the surface of TiO2. The Pd/TiO2 was deposited on the alumina substrate with a comb-like gold electrode, then it was calcined at various temperature in air. XPS shows the Pd on the Pd/TiO 2 film is in the form of oxide, while FSEM showed that the PdO/TiO2 film is porous. The photoconductivity of the PdO/TiO 2 film is measured under visible light in room temperature in pure N2 or N2 doped with 1000 ppm O2 respectively. The results show that, in pure N2, the photoconductivity of the PdO/TiO2 film is strongly influenced by the sintering temperature. The photoconductivity of the sample sintered at 350°C was higher than that in 550°C. The photoconductivity of the film is also influenced by trace O2 in N2. Under continuous light irradiation, the photoconductivity of the film is responded to the doping of O2 in N2, which could decrease the photoconductivity remarkably. By this phenomenon, it is suggested that a trace oxygen sensor can be developed, which can work in room temperature.