Herein, a novel 2D/0D Bi 12O 17Cl 2/AgI (B 12OC/AgI) heterojunction with enriched oxygen vacancies was synthesized via an in-situ growth method for enhanced mineralization performance of antibiotics. It was confirmed that owing to the formation of type II heterojunction between Bi enriched Bi 12O 17Cl 2 and AgI, the spatial separation of photoinduced electrons and holes was improved efficiently, thereby promoting the utilization rate of photogenerated charge carriers. As a result, the B 12OC/AgI-15 exhibited the best degradation performance and the degradation efficiency of TC within 15 min was 95.02%. The corresponding kinetic constants of B 12OC/AgI-15 to TC were 4.30 and 9.63 times higher than that of bare Bi 12O 17Cl 2 and AgI, respectively. Moreover, it was found that the combination of Bi 12O 17Cl 2 and AgI can effectively prevent the coupling of photoelectrons with interstitial Ag + to form metal Ag, which can improve the anti-photocorrosion ability and ensure structure stability of B 12OC/AgI heterojunction. In addition, the intermediates and degradation pathways of TC over the B 12OC/AgI were discussed in detail.