In this paper, distillers’ grains biochar (DGBC) was facilely gained by processing the distillers’ grains produced in Chinese Baijiu brewing, and the DGBC was used to modify BiOCl. The prepared DGBC/BiOCl composite photocatalysts show elevated visible light-driven catalytic performance. X-ray diffraction (XRD) and scanning electron microscope (SEM) suggest the presence of DGBC affects the crystal growth and microscopic morphology of BiOCl. The low-temperature electron paramagnetic resonance (EPR) test affirms more oxygen vacancies (OVs) exist in the DGBC/BiOCl composite photocatalysts. The 0.75-DGBC/BOC photocatalyst holds the highest efficiency for removal of rhodamine B (RhB), tetracycline (TC) and Cr (VI) compared with BiOCl, commercial TiO₂ (P25) and other DGBC/BiOCl composites. Given the experimental results, the enhanced visible light responsive performance originates from the rich OVs introduced by the modification of BiOCl with DGBC and the higher separation rate of photoexcited carriers.