Self-assembled nanorods/nanowires of CdS were successfully synthesized by a solvothermal method at 200 oC for 5, 10 and 20 h using sodium dodecylsulfonate as a capping reagent. X-ray diffraction (XRD) patterns of all CdS samples can be indexed to pure phase of hexagonal CdS structure. The degree of crystallinity of CdS was increased with the increase of holding reaction time from 5 h to 20 h. Transmission electron microscopic (TEM) images revealed that the product synthesized by the solvothermal method at 200 oC for 20 h contained self-assembled flower-like CdS nanostructure. The UV-visible absorption of self-assembled flower-like CdS nanostructure shows excellent absorption in UV-visible region with the absorption peak at 481 nm. Photocatalytic efficiency of the as-prepared CdS samples was investigated through rhodamine B (RhB) degradation under visible light irradiation. In this research, the self-assembled flowerlike CdS nanostructure has the highest degradation of 94.91 % within 80 min.