Abstract: TiO2 nanotube arrays were prepared by potentiostatic anodization of pure Ti foils in an approximately neutral solution. The effect of anode voltage, anodization time and the mass concentration of the fluorion in electrolyte on the micromorphology of TiO2 nanotube arrays was studied. The results showed that the pore diameters and the wall thickness of TiO2 nanotubes ranges from 30 nm to 50 nm and 20 nm to 25 nm, respectively. The TiO2 nanotube arrays film is amorphous before annealing, and then turns into anatase and rutile after annealing at 550°C, in which anatase is dominant. Decolorization experiments of methyl orange(MO) wastewater indicated that the fabricating conditions also influence the decolorization rate of MO, and the higher photocatalytic decolorization rate is obtained by the regular TiO2 nanotube array film. Comparing with direct photolysis, the photocatalysis of TiO2 nanotubes can increase the decolorization rate of MO by 40%.