Abstract: The MoS₂/g-C₃N₄ catalyst was prepared by using the impregnation and calcination methods. Its crystal form, morphology and photoelectrochemical properties were characterized by using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, ultraviolet-visible diffuse reflectance spectroscopy, steady fluorescence spectrum, respectively. The MoS₂/g-C₃N₄ catalyst was applied to the treatment of printing and dyeing wastewater. The results showed that the MoS₂/g-C₃N₄ catalyst had a porous layered structure and good response to visible light. Under the illumination conditions with its dosage of 2.0 g/L, pH=6 and the reaction time of 120 min, the MoS₂/g-C₃N₄ catalyst had the highest chroma and chemical oxygen demand (COD) removal rates for printing and dyeing wastewater, which are 89.78% and 65.57%, respectively. After the MoS₂/g-C₃N₄ catalyst was recycled for 5 times, the chroma and COD removal rates of printing and dyeing wastewater still reached 77.28% and 53.26%, respectively, indicating its good stability.