Anodization of some valve metals such as titanium (Ti), leads to the self-organized nanostructured. In this work we present a systematic study of the formation, characterization, and refractive index of titanium dioxide (TiO2) nanotubes. The anodizing of Ti foil was performed in ethanol-H2O electrolyte (50%) mixture containing 0.3 wt% HFat different voltages and durations. It was found that the current density, measured during preparing the samples, is controlled by the variation of the anodizing voltage. In addition, increasing the applied voltage used in the anodizing process resulted in an increase of the calculated refractive index of nanostructured samples. The results also revealed that the nanotube diameter, wall thickness, center-to-center nano-tube, and porosity, refractive index are affected by changing the anodizing parameters.