Because nanoparticles have particular characteristics, such as small size and surface effects, nano-TiO₂ is widely used in air purification, wastewater treatment and self-cleaning. In recent years, TiO₂ photocatalysis has thoroughly explored as a new titanium implant surface treatment method. Photocatalytic performance is better for TiO₂ nanowires than for nano-TiO₂ particles. Hence, these nanowires have received widespread attention with regard for their more specific surface area and surface energy, improved charge carrier transport efficiency, and enhanced charge collection efficiency. Photon-generated carrier transport moves in a one dimensional straight path along a nanowire, and this could decrease photoelectron loss. In this paper, we summarized the principles underlying, factors that influence, and applications involving TiO₂ nanowire photocatalysis. Additionally, we describe its method of preparation and toxicity.