Abstract The low temperature RF plasma treatment was used to control the surface chemistry and optical property of TiO 2 thin films deposited by RF magnetron sputtering with a very good uniformity at 300 °C substrate heating temperature. The XRD pattern indicates the crystalline structure of the film could be associated to amorphous structure of TiO 2 in thin film. The plasma treatment of TiO 2 film can increase the proportion of Ti 3+ in Ti2 p and decrease in carbon atoms as alcohol/ether group in C1 s at the surface. The optical transmittance of the film was enhanced by 50% after the plasma treatment. The surface structure and morphology remain the same for untreated and low-pressure plasma-treated films. Therefore, increase in the optical transmission could be due to change in surface chemistry and surface cleaning by plasma treatment.