BiOCl hierarchical microspheres assembled from nanosheets with exposed {001} facets were successfully synthesized using PEG-2000 as template by a one-pot room-temperature hydrolysis method. The PEG-modified BiOCl photocatalyst exhibits a significantly enhanced RhB photosensitized degradation activity under visible light. After 10 min white LED irradiation, the degradation efficiency of RhB by the PEG-modified BiOCl sample S_0.07 reaches 99.5%. The degradation rate constant of the PEG-modified sample S_0.07 over RhB is 0.4568 min⁻¹, which is 6.76 times that of the unmodified sample S₀ (0.0676 min⁻¹). After 4 min of xenon lamp (λ ≥ 420 nm) irradiation, the degradation rate of RhB by S_0.07 is almost 100%. The exposed {001} facets with surface defects contribute to the superior adsorption capacity of BiOCl towards RhB, which immensely accelerates the electron transfer efficiency from the excited RhB into the conduction band of BiOCl, forming superoxide radical (˙O₂⁻) active species to degrade the pollutants. Moreover, the superior RhB-sensitized BiOCl system provides high photocatalytic degradation activity over MO. This work provides a facile and efficient BiOCl synthesis method that is conducive to large-scale production and simultaneously opens up new ideas for the synthesis of other photocatalysts.