To date, it still remains a big challenge to develop a new photocatalyst for photocatalysis technology. Herein, the BiOF photocatalyst with a regular nanosheet shape have been, for the first time, prepared by a simple hydrothermal method. The samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), ultraviolet-visible diffuse reflectance spectrum (UV-DRS), electrochemistry impede spectrum (EIS) and nitrogen sorption isotherms. Also, the Ab initio density functional theory (DFT) calculations have been carried out to give an insight into the energy * Corresponding author. Tel./2 band and electronic structures of BiOF. Further, rhodamine B (RhB) is chosen as the representative dye pollutant to evaluate the photocatalytic activity of BiOF. The results show that the uniform BiOF nanosheets grow preferentially along the [110] and [100] orientation, and 75.4% of (002) facets are exposed. After 60-min ultraviolet light irradiation (< 420 nm), 79.3% of RhB is degraded by BiOF, while only 33.7% of RhB is degraded by commercial rutile TiO 2 . The apparent kinetic rate constant (0.02534 min −1 ) over BiOF is 3.88 times as high as that (0.00652 min −1 ) over rutile TiO 2 . Moreover, the calculation results demonstrate that the high-energy (002) facets are more active than the low-energy (020) and (200) facets. For the layered BiOF, there is an internal electric field (IEF) perpendicular to the [Bi 2 O 2 ] 2+ slabs and fluorine anionic slabs, favors for the efficient separation of photogenerated electrons and holes. It is the synergetic effect of surface structure and bulk IEF that greatly improve the activity of BiOF nanosheets. We expect that bulk IEF adjustment is another new strategy to develop new, efficient photocatalyst for the layered materials.