Unlike most previously reported experiments in which nano belts were prepared using 10 M sodium hydroxide, a series of TiO2 precursor nanobelts with diameters ranging from 60 to 600 mn were successfully synthesized in our laboratory via a hydrothermal process using different concentrations of NaOH aqueous solutions and a commercial TiO2 powder (P25) as the raw materials. The reaction temperature was unexpectedly high at 260 degrees C. The formation process of TiO2 precursor nanobelts was investigated in terms of the morphological variations during a particle-to-nanobelt transition. Based on the detailed structural analysis of TiO2 precursor nanobelts, a rational mechanism has been proposed for the growth of the nanobelts. In addition, X-ray diffraction (XRD) of the nanobelts and degradation-efficiency test of a Rhodamine B (RhB) dye solution revealed that the precursor nanobelts should be heat treated at 650 degrees C to produce highly crystalline anatase materials.