The visible-light-responsive composite photocatalyst is beneficial to improve the solar energy utilization efficiency through the coupling of narrow bandgap materials. In this work, CdS nanowires were prepared by hydrothermal method, and then BiOBr/CdS composite materials with different mass ratios were successfully prepared by a simple two-step sonography-precipitation method using CdS nanowires as a deposition template. The photocatalysts were characterized by XRD, SEM, XPS, TEM, and other methods. Rhodamine B (RhB) was used as a model pollutant to evaluate the photocatalytic activity of BiOBr/CdS catalysts with different mass ratios. The photocatalytic test results show that the composite photocatalyst containing 60% BiOBr has the highest photocatalytic activity, which indicates that it is related to the decrease in photogenerated charge recombination rate. Subsequently, the electrochemical and physical methods were used to illustrate the electron transfer mechanism and the main active center of the as-prepared samples. Free radical capture experiments reveal that holes are the main active species in the photocatalytic process of composite samples. [GRAPHICS] .