Porous anodic alumina (PAA) with regular channel structure was chosen as a template, and highly ordered TiO2 nanofibrils arrays were fabricated within the pores of PAA by a sol-gel process. A series of TiO2 nanostructures obtained after the TiO2/Al2O3 composite film was treated with the NaOH for different times. Contact angle measurements indicated that the surface structure strongly affected the wetting behavior of the TiO2 nanofibrils. The wettability of the surface changed from hydrophilic to hydrophobic when the structure of aligned nanofibrils with end tips was obtained.