Herein, we report the synthesis of novel narrow band gap phosphorus sulfide quantum dots (PSQDs)-modified bismuth oxybromide (Bi 24 O 31 Br 10 ) heterojunction (noted as BOB/PS) for the highly efficient photo-degradation of hazardous organic pollutants including rhodamine B (RhB), methyl orange (MO), and malachite green (MG). Such a high photocatalytic activity of BOB/PSQDs heterojunction derives from the improved visible-light response capacity, high surface area/pore volume, and suitable band structure for efficient electron transfer to generate reactive oxygen species (ROS). ROS trapping experiments demonstrate that hydroxy ( * OH) and superoxide radicals ( * O 2 À ) play important roles in the photo-degradation. A possible S-scheme mechanism for the enhanced photocatalytic activity of BOB/PS is proposed.