A variety of technologies have been used to solve the problems of deep chromaticity, high concentration of organic matter and complex composition of printing and dyeing wastewater, but no major breakthrough has been made in general. Photocatalytic technology shows great advantages in wastewater treatment, and the development of strong oxidizing photocatalytic materials has potential application value. In this study, BiOCl/SrFe12O19 magnetic composite photocatalysts with various ratios of components were prepared using a hydrothermal method. The structure of the photocatalyst was characterized by XRD, PL, EIS and XPS. The photocatalytic performance of the composite sample was evaluated by RhB degradation experiment. The results showed that the optimum sample BiSr-10 had a degradation rate of 99.24 % for RhB, indicating excellent photocatalytic performance. The successful combination of SrFe12O19 and BiOCl facilitated to improve the photodegradation efficiency of RhB by composite photocatalytic materials. And the photocatalytic efficiency for RhB remained close to 82.8 % after five cycles of stability experiments. Analysis of the possible photocatalytic mechanism was based on the aforementioned results. In summary, the prepared BiOCl/SrFe12O19 composite photocatalytic material will bring a new breakthrough for wastewater treatment.