Abstract: Oxygen vacancy-mediated BiVO₄ nanosheets were synthesized with the hydrothermal and sintering methods. The structure and hydrogen production properties of BiVO₄ nanosheets with different oxygen vacancy (O_V) contents were studied with X-ray diffractometer(XRD), electron spin resonance spectroscopy, high resolution transmission electron microscope, UV-Vis spectrophotometer, fluorescence spectrometer and the photocatalytic O₂ evolution system. Through the regulation of Ov content, the optical absorption and optoelectronic properties of BiVO₄ nanosheets were optimized, and the photocatalytic O₂ production efficiency was greatly improved. The results showed that the optical absorption of BiVO₄ nanosheets in the visible region was significantly enhanced after O_V introduction, and the absorption edge of the sample is obviously red-shifted with the increase of O_V content. The introduction of an appropriate O_V amount could significantly improve the separation of photogenerated electrons and holes, thus improving the utilization rate of photogenerated electrons. The photocatalytic O₂ production rate of BiVO₄-O_V2 nanosheets was about 433 μmol/(h·g), which was about 10 times higher than that of BiVO₄.