The ZnWO 4 nanorods doped with cadmium ions have been successfully synthesized by a hydrothermal crystallization process. The products were characterized in detail by multiform techniques: X-ray diffraction (XRD), energy dispersive X-ray analysis (EDS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results of the photocatalytic degradation of rhodamine B (RhB) in aqueous solution showed that cadmium ions doping greatly improved the photocatalytic efficiency of ZnWO 4 nanorods. The Cd-doped ZnWO 4 nanorods with atomic ratio of Cd to Zn being 0.06 had the best activity in photo-degradation of RhB in aqueous solution under UV light irradiation, when the nanorods have prepared at pH 8.