Black phosphorus (BP) is highly regarded in photocatalysis for its bandgap thickness dependency, high hole mobility, and broad visible light absorption. This study introduces a simple hydrothermal method to construct a BP QDs/BiVO4 direct Z-scheme heterojunction. The composite’s crystal structure, morphology, and photochemical properties were comprehensively characterized. The photocatalytic activity was evaluated using Rhodamine B (RhB) degradation under visible light. Notably, BP QDs0.12%/BiVO4 exhibited exceptional performance, achieving a 95.4 % RhB degradation after 100 min, three times higher than BiVO4 alone. The direct Z-scheme heterojunction played a pivotal role in facilitating O2− and h+ involvement in the degradation process. The interfacial interaction between BP QDs and BiVO4 significantly enhanced BiVO4′s visible light absorption, preserving its strong oxidation–reduction capacity. This enhancement was further corroborated by DFT simulation calculations. Overall, this study presents a novel approach for constructing efficient Z-scheme photocatalysts based on BP QDs, laying a solid foundation for their application in the field of photocatalytic degradation.