Abstract: A series of bismuth oxybromide photocatalysts were fabricated via a one-step hydrothermal method through pH value adjustment. The as-prepared photocatalysts were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), UV-vis diffuse reflectance spectroscopy (UV-vis DRS) and photoluminescence spectroscopy (PL). The photocatalytic activities of the as-prepared samples were examined by degradation of Rhodamine B (RhB), methyl orange (MO) and phenol. The results indicate that the B9 displayed the highest photocatalytic activities. The enhanced photocatalytic activity can be attribute to enhanced absorption in the visible region and the decreased recombination efficiency of photogenerated charge carriers. The effect of hydrothermal pH value on the composition and morphology was explored and a synthesis process of bismuth oxybromide was proposed.