Both Ti foil and porous Ti were anodized in 0.5%HF and in ethylene glycol electrolyte containing 0.5%NH 4 F (mass fraction) separately. The results show that TiO 2 nanotubes can be formed on Ti foil by both processes, whereas TiO 2 nanotubes can be formed on porous Ti only in the second process. The overhigh current density led to the failure of the formation nanotubes on porous Ti in 0.5%HF electrolyte. TiO 2 nanotubes were characterized by SEM and XRD. TiO 2 nanotubes on porous Ti were thinner than those on Ti foil. Anatase was formed when TiO 2 nanotubes were annealed at 400 °C and fully turned into rutile at 700 °C. To obtain good photodegradation, the optimal heat treatment temperature of TiO 2 nanotubes was 450 °C. The porosity of the substrates influenced photodegradation properties. TiO 2 nanotubes on porous Ti with 60% porosity had the best photodegradation.