nanopowders with anatase structure were firstly prepared by controlling the pH value of a precursor solution without any heat-treatment at room temperature. The prepared nanopowders were hydrothermally treated in 10M NaOH solution at . Then, the samples were washed in DI water or 0.1M HCl. The nanotubes were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). The gas sensitivity of nanotubes for toluene gas was also investigated. The results show that nanotubes can be prepared by hydrothermal treatment. The morphology of nanotubes prepared by 0.1M HCl washing is destroyed to some extent. nanotubes with DI water washing show better sensitivity than that with 0.1M HCl washing.