In the work, visible-light-driven hierarchi- cal Bi3.84W0.16O6.24 photocatalysts have been synthe- sized by a facile hydrothermal strategy. The micro- structures and photocatalytic activities of Bi3.84W0.16- O6.24 photocatalysts were finely tuned just by adjust- ing the pH values of reaction solutions with different alkalis. The as-prepared samples were physically characterized by X-ray powder diffraction, field- emission scanning electron microscopy, and ultra- violet-visible diffraction reflection spectroscopy. When evaluated by the photocatalytic degradation of methyl orange (MO) under the visible-light irra- diation, Bi3.84W0.16O6.24 samples with distinct mi- cro-structures showed different photocatalytic activities. Of Note, the hierarchical Bi3.84W0.16O6.24 sub-microspheres constructed by nanoflake building blocks demonstrated the highest photocatalytic ac- tivity forthe degradation of MO under the visible-light irradiation.