In the present work, we demonstrate the feasibility to form large inner diameter TiO2 nanotubes by anodization of Ti in a HF/ethylene glycol electrolyte. In order to achieve the large inner diameter TiO2 nanotubes, optimization of the anodization condition is required. We discover the key factors in the formation of large inner diameter TiO2 nanotubes are concentration of water in the electrolyte, anodization temperatures, and high-applied potential. Under optimum conditions, the inner diameters of TiO2 nanotubes are 379 nm. The results are approximately 3 folders larger than the general case.