In this work, TiO2/Ti2O3 composite catalysts were prepared by simple one-step thermal treatment method at various temperatures. The morphology and structure of as-prepared samples have been examined by XRD, TGA and SEM. The XRD characterization results revealed three-phase mixture in sample treated at 550°C, while at 650°C phase transformation from TiO2 anatase to TiO2 rutile and particle size growth was observed. Moreover, the effect of treatment temperature on the photocatalytic degradation of caffeine was evaluated under UV light irradiation. Results indicated that TiO2/Ti2O3-550 exhibited higher catalytic activity than others achieving complete caffeine removal in 60 min.