A novel nanocomposite in the role of photocatalyst was prepared by composition of zinc sulfide (ZnS) nanoparticles with carbon nanofibers (CNFs) and was characterized. The XRD, EDX, and FE-SEM analysis revealed that ZnS is successfully embedded in CNFs matrix. The DRS results indicated that supporting of ZnS by CNFs led to a decrease of the band gap energy. The photocatalytic degradation of a hazardous xanthine dye, Rhodamine 6 G (Rh-6G), by the prepared ZnS/CNFs composite was examined from the kinetics point of view. Nonlinear regression analysis was used to develop a mathematical kinetics model based on the Langmuir-Hinshelwood mechanism, and an empirical equation was obtained for the estimation of apparent pseudo-first-order rate constant (k ) as a function of operational parameters (viz. initial dye concentration, ZnS/CNFs content, pH, and irradiation intensity). Based on the results, k increased with an increase ZnS/CNFs content, pH, and UV light intensity, whereas it decreased by increasing the initial Rh-6G concentration. Moreover, a new kinetics model was obtained based on proposed elementary steps to determine k . In the final stage of the work, intermediate materials produced within photocatalytic degradation of Rh-6G dye were detected by GC-MS analysis.