A new mixed-phase (anatase/rutile) TiO2 with mesoporous structures and smaller crystal size (3-5 nm) was successfully synthesized by a facile sol-gel method at a lower calcination temperature (100 °C). Rhodamine B can be completely decomposed in the presence of the as-synthesized nanocomposite after only 60 minutes under visible light. Therefore it is believed to be a promising candidate for wastewater treatment.