Sulfur nanoparticles have been successfully prepared from sodium thiosulfate in the presence of Albizia julibrissin fruits extract at room temperature. The resulting sulfur nanoparticles were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). XRD characterizes the final product as highly crystalline sulfur, exhibited high purity, spherical shape with average particle size of about 20 nm, and particle size distribution in range 10 nm to 100 nm. The particle size of nanoparticles could be controlled by tuning the amount of Albizia julibrissin fruits extract. FT-IR analysis of S-NPs indicated a new chemistry linkage on the surface of sulfur nanoparticles. This suggests that Albizia julibrissin fruits extract can bind to sulfur nanoparticles through carbonyl of the amino acid residues in the protein of the extracts, therefore acting as stabilizer and dispersing agent for synthesized sulfur nanoparticles. This research provides a greener and more environment-friendly synthetic method for the production of sulfur nanoparticles for antibacterial and antifungal activities.