Abstract: Nano semiconductor photocatalyst TiO₂ was prepared by a sol-gel method with butyl phthalate as the precursor. The structures of the TiO₂ photocatalyst were characterized by Brunaure-Emmett-Teller (BET), X-ray Diffraction (XRD) and X-ray Photoelectron Spectroscopy (XPS). And the photocatalytic antibacterial performance on Escherichia coli and Staphylococcus aureus were investigated using the flat colony counting method. The results showed that the TiO₂ photocatalyst had a higher purity, larger specific surface area was 76.5 m²/g, and smaller particle size was 16.9 nm with the characteristic peaks of TiO_x, -OH and COO-. Besides, there was a rutile and anatase mixed crystal structure with anatase structure as the dominant phase, which was in favor of improving photocatalytic properties of TiO₂. Under the irradiation UV light at the wavelength of 254 nm for 30 min, the removal efficiency of Escherichia coli and Staphylococcus aureus on TiO₂ was up to 97.8% and 99.4%, respectively. And it showed that TiO₂ was an environmentally friendly functional material with good bactericidal performance.