A Bi6O6(OH)3(NO3)3·1.5H2O (BBN)/Bi2O2CO3 (BOC) heterojunction was designed for the first time via afacile hydrothermal method. The photocatalytic performance of catalysts was evaluated by degrading Rhodamine B(RhB) under simulated solar light irradiation. It was found that the degradation rate of RhB by 25 wt%BBN/BOC wasdramatically increased about 1.5 and 4.7 times compared with that of pure BOC and BBN, respectively. The enhancedphotocatalytic performance migth be attributed to the effective separation of photoinduced electron-hole pairs, benefitingfrom the construction of heterojunction. Furthermore, the mechanism upon BBN/BOC composites photocatalystwas investigated, expecting this work will bring new insight into the theoretical study and application of semiconductorsmaterials.