A series of Bi2O3/Bi2O4 composites were prepared by calcining raw materials with different NaBiO3/KOH mass ratios. The Bi2O3/Bi2O4 photocatalysts were characterized by the various measurements and their photocatalytic performance was assessed by degradation of 17α-ethinyl estradiol (EE2). The Bi2O3/Bi2O4 photocatalysts have wider visible light absorption and lower fluorescence emission intensity than the commercial Bi2O3. So, they displayed superior performance in the degradation of EE2. After the adsorption equilibrium of EE2 was reached, the degradation efficiency of Bi2O3/Bi2O4 for EE2 can reach a maximum value of ~ 100% in 12 min under the visible-light illumination. Degradation analysis results indicated that both holes (h+) and superoxide radical (·O2−) can affect the degradation efficiency of EE2.