Herein, monoclinic ZrO₂ (m-ZrO₂) nanostructures were prepared by a facile one-step hydrothermal method. As-prepared products showed ring-like nanostructures with an average size of ~ 23.1 nm and high surface area. The ring-like m-ZrO₂ nanostructures exhibited broad absorption spectra in the visible region (400–800 nm) and a low band gap of 3.7 eV. Moreover, blue emission was also shown by m-ZrO₂ nanostructures under the excitation of wavelength 300 nm. As-prepared m-ZrO₂ nanostructures show high photocatalytic performance under UV irradiation. The lower band, high surface area and presence of oxygen vacancies may be attributed to the excellent performance of ring-like m-ZrO₂ nanostructures as a photocatalyst.