Developing defects on the surface of TiO₂ nanoparticles by mechanical treatment is a fascinating approach to enhance photocatalytic efficiency. However, it poses risks to producing bulk defects and phase transformation, which seriously deteriorates photocatalytic performance. Here, activating TiO₂ nanoparticles was elaborately fulfilled by using dielectric barrier discharge plasma assisted ball milling (DBDP-milling) as it imposes plasma to nano-scaled particles along with soft mechanical impact. The evolution of surface properties of TiO₂ nanoparticles with DBDP-milling durations was inspected using a Fourier transform infrared (FTIR) and an X-ray photoelectron spectrometer (XPS), while the morphology and structure were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Raman spectroscopy. Results showed that DBDP-milling developed a considerable number of oxygen vacancies in TiO₂ nanoparticles as well as bulk defects free. These TiO₂ nanoparticles formed agglomerates with BET surface area of 37.40 m2/g and exhibited enhanced photocatalytic efficiency.