NiS/CdS nanocomposites with good visible-light-induced photocatalytic activity were successfully prepared via a facile two-step process. In the composites, well-crystalline NiS nanoparticles grew on the surfaces of CdS particles prepared by a hydrothermal method or by microwave method. The structural features were investigated by powder X-ray diffraction and transmission electron microscopy. The as-synthesized NiS/CdS nanocomposites exhibited good photocatalytic performance in the degradation of quinoline under visible light irradiation. The amount of NiS loading and the phase of CdS affected the photocatalytic performance of NiS/CdS nanocomposites. In addition, the effects of operational parameters such as the amount of photocatalyst and initial pH on the photodegradation of quinoline have been analyzed.