Novel C, N, and S-doped ZnO nanoparticles were prepared by a solid phase reaction. The catalyst was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The results showed that crystallite size of synthesized C, N, and S-doped ZnO were in nanoscale.  The degradation was studied under different conditions such as the catalyst concentration, concentration of drug, initial pH value and presence of electron acceptor. The results showed that photocatalytic degradation of drug was strongly influenced by these parameters. The best conditions for the photocatalytic degradation of diclofenac sodium were obtained. The optimum concentrations of N, S, C -ZnO was found to be 0.44g/L. The photodegradation efficiency of diclofenac sodium decreased with an increase in the initial concentration of diclofenac sodium. In acidic solutions, photocatalytic degradation efficiency was higher than in alkaline solutions. The photodegradation efficiency of diclofenac sodium was accelerated by addition of a small amount of K₂S₂O₈ and H₂O₂.