In this work, a series of flower-like Bi/BiOClxBr(1−x) heterojunction photocatalysts have been developed. Bi nanoparticles were grown on the BiOClxBr(1−x) nanosheets via an in situ chemical reduction with the assistance of cetyltrimethylammonium chloride and cetyltrimethylammonium bromide aqueous solution. The in situ growth of Bi nanoparticles on the BiOClxBr(1−x) nanosheets could not only give rise to the optical absorption in the visible region, but also promote the photocatalytic performance of BiOClxBr(1−x). Bi/BiOCl0.8Br0.2 exhibited the highest photocatalytic performance, which could completely degrade RhB in 12 min under the UV light irradiation and 6 min under visible light irradiation, respectively. Moreover, holes and superoxide radicals were verified to be the primarily active species in the photocatalytic process.