This work aims to prepare a new biodegradable antibacterial packaging material by polylactic acid (PLA) added with nano-titanium dioxide (Nano-TiO2). Antibacterial agent Nano-TiO2 was added into PLA to prepare Nano-TiO2/PLA antibacterial film by solution casting method. Antibacterial rate, mechanical property and moisture permeability of the antibacterial film were tested. The modification results were evaluated by scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction. When the mass fraction of Nano-TiO2 was 4%, the antibacterial rate of the antibacterial film against staphylococcus aureus was 90.27%; its tensile strength was 23.2 MPa; its breaking elongation was 2.2%; and its water vapor permeability coefficient was 2.3×10‒13 g•cm/(m2•s•Pa). Nano-TiO2/PLA antibacterial film has excellent antibacterial effect, and can be used for food, medicine and other packaging.