The g-C3N5/β-Bi2O3 (CN/BO) composites were prepared by hydrothermal and calcination method using g-C3N5, Bi(NO3)3.5H2O and Na2C2O4 as raw materials. The structure, morphology and photoelectric properties of CN/BO were characterized by XRD, SEM, TEM, UV-Vis DRS, PL and EIS. The photocatalytic degradation performance of CN/BO was tested for TC in tetracycline hydrochloride (TC) aqueous solution under simulated natural light conditions. The effects of TC aqueous mass concentration, CN/BO dosage, solution pH and inorganic anion are investigated on the degradation rate of TC, as well as the substrate universality and recycling performance of CN/BO. And the mechanism of photocatalytic degradation of TC is speculated by CN/BO. The experiment results indicate that photocatalytic activity of CN/BO is better than a single material. 50CN/BO (the mass of g-C3N5 and β-Bi2O3 were equal) has the best photocatalytic activity. When 20 mg 50CN/BO are added in 30 mL, 20 mg/L TC solution for illumination 90 minutes, the photodegradation rate of TC and total organic carbon (TOC) removal rate are 94.1% and 72.4%, respectively. The degradation rate of six common water pollutants, such as Rhodamine B (RhB) and malachite green (MG), is 81.0%~99.8% illumination 60 minutes. CO32? can reduce the degradation rate of TC, but S2O82? can increase the degradation rate of TC in solution. The photocatalytic performance of 50CN/BO is basically unchanged when the solution of pH is 6-12. 50CN/BO is used for 5 times and still maintain high catalytic activity. The main active species are h+ and ?O- 2 groups in degradation reaction. S-type heterojunction is formed between β-Bi2O3 and g-C3N5 to improve the charge separation and transfer ability also to increase the number of active groups participated in the photodegradation reaction of CN/BO.