A CdS/SnS nanocomposite was prepared using a simple hydrothermal method and used as a sensitive material for the detection of carbon disulfide (CS2) based on cataluminescence (CTL). The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectrometry (EDS) and X-ray photoelectron spectroscopy (XPS). The results show that the CdS/SnS nanocomposite sensor has a high sensitivity to CS2 at a relatively low operating temperature (162 °C); the response time is about 3 s, and the recovery time is about 16 s. The modification of CdS effectively enhances the sensitivity of SnS sensors. The CTL intensity shows a good linear relationship at gas concentrations ranging from 6.75 to 168.75 ppm (R2 = 09974), and the limit of detection (LOD) of CS2 reached 0.96 ppm. In addition, the CdS/SnS sensor has excellent selectivity and good stability towards CS2. The mechanism of the sensor is discussed in detail. This research shows that CdS/SnS has great potential for the detection of CS2.