TiO2 porous films were prepared by anodization with different patterns of applied voltage. The formation mechanism of TiO2 porous films was discussed through experiment phenomena and SEM observation. The results showed that the formation of TiO2 porous films by anodization was controlled by voltage

barrier thickness when one-step voltage method or continuous voltage method was applied.However

the formation was controlled by voltage

barrier thickness

and interface state of electrolyte/barrier when two-step voltage method was used. The range of nano-pore diameter and nano-pore density of the TiO2 film could be extended with two-step voltage method in the same process condition.