This study presents a green approach on synthesizing cadmium sulfide nanoparticles using plant Panicum sarmentosum. The prepared cadmium sulfide nanoparticles were characterized by UV- Visible spectrophotometer, X- Ray Diffraction (XRD), Fourier Transformation Infrared (FTIR), Scanning Electron Microscope (SEM), X- Ray Fluorescence (XRF) and Thennal Gravimetric Analysis (TGA) respectively. The UV- Vis spectroscopy analysis revealed the formation of cadmium sulfide nanoparticles by exhibiting the typical surface Plasmon absorption maxima at a wavelength between 300- 400 nm as observed. XRD analysis result revealed the cubic shape with size 4.6 nm of CdSNPs. SEM obtained the infonnation regarding to the surface morphology. XRF analysis confirmed the presence of cadmium and sulphur in nanoparticles. TGA result proven that CdSNPs is more thermal stable than plant material. The presence of alcohol/phenol (OH), amide (NH) and carboxylic functional group were confirmed by FTIR analysis. Antibacterial activity of CdSNPs against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) was accomplished by agar Well diffusion method with increasing concentration of nanoparticles and enlarged inhibition zone was noticed. The characterization results revealed that cadmium sulfide nanoparticles were successfully synthesized through Panicum sarmentosum as well as the outcome of antibacterial activity showed that the synthesized cadmium sulfide nanoparticles had an inhibiting activity against Escherichia coli and Staphylococcus aureus.