One-dimensional ZnFe2O4-decorated CdS 0D/1D composites were successfully prepared by a low-temperature hydrothermal method. The existence of ZnFe2O4 nanoparticles could greatly prevent the CdS nanowires from agglomerating. Compared with primary CdS nanowires and ZnFe2O4 nanoparticles, the photoactivity of CdS/ZnFe2O4 composites with the optimal ratio was respectively enhanced by 2.3 and 6.6 times in the process of photodegrading organic molecules. The proposed photocatalytic mechanism was verified by a radical trapping test. The improved stability and the prolonged carriers lifetime in the composites were ascribed to the existing built-in field in the interface, facilitating the fast separation of photoinduced charge carriers. It was further validated by the room-temperature photoluminescence and the electrochemical impedance spectra.