Using bismuth nitrate and cerous ammonium nitrate as raw materials, aqueous ammonia as precipitator, pure and cerium-doped bismuth oxide photocatalysts were prepared through coprecipitation process. The phase composition and microstructure were investigated by XRD, SEM and TEM. The results showed that the pure and cerium-doped bismuth oxide photocatalysts were α-Bi2O3 and the sizes were all around 50 nm. Under the irradiation of visible light, the photocatalytic properties of samples were investigated by using degradation of Orange Ⅱ as the simulative reaction．The results showed that the photocatalytic degradation efficiency increased with the increasing of Ce4+ introduction. The photocatalyst with Ce4+/Bi3+ ratio of 20:80 performed 98% degradation efficiency. In addation, weak acid environment showed a better degradation efficiency.