The porous platelet-shaped alpha-Bi2O3 photocatalyst was successfully synthesized by a novel hydrothermal-calcination method assisted with ethylenediamine and polyvinylpyrrolidone. The physical and chemical properties of alpha-Bi2O3 photocatalyst were characterized based on XRD, XPS, SEM, TEM, EDS, UV-Vis DRS, and PL techniques. The influence of preparation conditions on the formation of alpha-Bi2O3 photocatalyst was investigated, and the effect of catalyst dosage and pH value on the EE2 removal rate was also investigated. The synthesized porous platelet-shaped alpha-Bi2O3 photocatalyst exhibited excellent photocatalytic activity for 17 alpha-ethynylestradiol (EE2), and 97.8% of EE2 was removed after 75 min of visible light irradiation using alpha-Bi2O3 as photocatalyst. The reaction rate constant over the porous platelet-shaped alpha-Bi2O3 photocatalyst was 11.6 and 11.4 times of that of traditional alpha-Bi2O3 and N-TiO2, respectively. The possible photocatalytic mechanism has been discussed on the basis of the theoretical calculation and the experimental results. The porous platelet-shaped alpha-Bi2O3 was a stable and efficient photocatalyst, proving that it is a promising photocatalyst.