In order to simplify the complex process of preparing TiO₂ nano bowl array by traditional method, the basic principle of two-step anodizing method was adopted. Namely, during the first and second anodizing process, oxidation voltage and electrolyte concentration all keep as before, but varying the anodizing time. The first anodizing time is 1 hour, and the second anodizing time changes from 0 s to 140 s. After the first anodizing, as the initial oxide layer for the second anodization, the residual bowl like pits on the surface of Ti-sheet may undergo three stages of growth. Firstly, the TiO₂ barrier began to grow longitudinally at the bottom of the pit. Then the dissolution of the electrolyte at the edge of the bowl took effect, and nano pores appeared in the bowl. Secondly, the longitudinal growth rate of the barrier layer and the dissolution rate of the electrolyte reached a relative balance. The bottom center of the TiO₂ barrier layer was first corroded, then the corrosion position changed around the bowl edge, and other nanopores were corroded laterally. Thirdly, the relationship between the longitudinal corrosion rate and the transverse corrosion rate was constantly changing, which showed that the depth of the nanopore in the bowl increased all the time, but the diameter of the bowl and the pore first increased and then decreased. Under the condition of the growth rate of TiO₂ barrier layer was in relative equilibrium with the chemical dissolution rate of electrolyte, and the longitudinal corrosion rate was relatively consistent with the transverse corrosion rate, TiO₂ nano bowl array with large pore diameter was synthesized. The optimal second anodizing time was 110 s, and the diameter of bowl was 133 nm.