TiO2 nanotube was synthesized successfully by hydrothermal process, using TiO2 powder and NaOH as the precurser. The micro-morphology and optical properties were characterized by XRD, SEM, HRTEM, UV Absorption Spectra Analyzer and Spectroradiometer, and the formation mechanism was also studied. The results showed that the product is anatase TiO2 nanotube with multiple layers wall, 10 nm~50 nm in the out-diameter, several micron to tens in the length, and opened in both of ends. The formation mechanism of the tube is coordinate with 3-2-1D model. The UV Absorption Spectra and PL spectra showed that the TiO2 nanotubes present blue-shift phenomenon compared to the raw material. The PL spectra also showed that at the visible band the luminous intensity of the TiO2 nanotubes increased obviously.