Abstract: In order to improve the photocatalytic performance of BiOI under visible light, the O-terminated Ti₃C₂ was prepared by etching Ti₃AlC₂ with NH₄HF₂, Ti₃C₂/BiOI composite materials were prepared by precipitation under ultrasonic radiation, using bismuth nitrate pentahydrate as bismuth source, potassium iodide as iodine source. The composition, morphology, structure, light absorption, transient photocurrent response and spectral response of Ti₃C₂/BiOI composite materials were characterized and measured by XRD, SEM, UV-vis, FTIR, EIS, I-t and PL. The photocatalytic degradation property of Ti₃C₂/BiOI composite material was carried out using methyl orange (MO) as targeted pollutant under simulated visible light. The results show that BiOI is successfully loaded on Ti₃C₂, the Ti₃C₂/BiOI composite material exhibits an appreciable photocatalytic activity under simulated visible light. The 6wt%Ti₃C₂/BiOI composite material shows the highest efficiency of 91.6% within 0.5 h, which is nearly 4.5 times higher than that of the BiOI. The O-terminated Ti₃C₂ as a cocatalyst to transfer photogenerated electrons in time, the charge separation is maintained in the charge depletion layer, which is helpful to improve the photocatalytic activity.