Abstract: Photocatalytic degradation was considered as a promising strategy for the elimination of hazardousorganic pollutants. In this work, a binary 3D/2D molybdenum disulfide supported oxygen-doped graphite carbon nitride (MoS₂/O-g-C₃N₄) heterojunctions was successfully fabricated by using a facile hydrothermal strategy. Meanwhile, the as-prepared photocatalysts were characterized by XRD, XPS, SEM, TEM, FTIR and PL. By these characterized observed the formation of Z-type heterojunction between MoS₂ and O-g-C₃N₄. Under visible light irradiation, when the loading of MoS₂ was 0.2%, MoS₂/O-g-C₃N₄ exhibited better photocatalytic activity, and the degradation rate of bisphenol A (BPA) is 92.6%, which is 7 times higher than that of pure g-C₃N₄. In addition, the close contact and mutual synergistic effect of the interface between MoS₂ and O-g-C₃N₄ significantly enhance the photocatalytic reaction active sites and visible light absorption capacity, and effectively improve the separation of photogenerated carriers. Using liquid chromatography-mass spectrometry technology (LC-MS) and capturing experimental results, the possible photocatalytic mechanism of the 0.2%MoS₂/O-g-C₃N₄ heterojunction composite material degrading crystal violet were proposed. This research provides a new method for the preparation of high-efficiency heterojunction photocatalysts.