Heterojunction semiconductor photocatalysis is an auspicious technique for clear up organic pollutants from water, and have been of valuable strategy in the area of photocatalysis. Herein, electrophoretic deposition procedure was used to prepare α-Bi2O3/CdS type-Ⅱ heterojunction photocatalysts. The results of PL, Raman, and EIS show that there is a heterojunction effect in α-Bi2O3/CdS, which is propitious to improve the separation efficiency of photogenerated electron-hole pairs. The DFT calculation reveals that the work function of CdS (4.57 eV) is higher than that of α-Bi2O3 (3.37 eV), which facilitates the migrating of e- from the CB of α-Bi2O3 to the CB of CdS, and the migrating of h+ from the VB of CdS to the VB of α-Bi2O3, thus the e--h+ pairs with high redox ability are retained. The performances were assessed by degrading methyl orange (MO), acid magenta under simulated visible light irradiation. Under simulated visible light irradiation, BC45 composite exhibited the highest degradation efficiency of 87% (MO) and 81% (acid fuchsin) for 4 h, which was about 2 times higher than that of CdS (MO) and (acid fuchsin). It is believed that the dual characteristics of H2O wettability and dye adsorption performance in α-Bi2O3/CdS composites promote photocatalytic process compared with single CdS and α-Bi2O3. The study could provide new insights to develop efficiently capable photocatalysts of the α-Bi2O3/CdS composites.