A room temperature oxygen sensor based on TiO2/graphene device was developed with an enhanced sensing performance by UV light. A logarithmic relationship between the sensing response and O2 concentration (from 134 ppm to 100%) was obtained. The sensor also shows an improved response and recovery with the durations of 193 s and 135 s at RT and atmosphere pressure, respectively. Herein, UV light was employed to excite electron-hole pairs in the TiO2 film and the photogenerated electrons were scavenged by graphene and percolated to the collecting electrode, while the holes recombined with the electrons within TiO2 film. This process will deplete the electron further thereby changing the conductivity of the device rapidly resulting in a much better sensing signal.