High-purity nanotubes and nanobelts could be controllably obtained in hydrothermal treatments of anatase TiO2 in concentrated NaOH solution depending on treating temperature and duration. Their structural features were studied employing X-ray diffraction, Raman, X-ray absorption fine structure, and electron diffraction characterizations. The results reveal that both the nanotubes and nanobelts might be of layered titanate structure. The similarity and difference among the nanotubes/nanobelts and other bulk titanates represented by trititanate H2Ti3O7 and lepidocrocite-type H(0.7)Ti(1.825)square(0.175)O(4.0)center dot H2O were also presented.