Industries that used nanoparticles has wide applications, among them are; in the production of cosmetics and pharmaceutical industries, therapies, and much more. Plants, algae, or microorganisms can be used in the synthesis nanoparticles, and combustion byproducts can also be used to make nanoparticles. In this study, silver nanoparticles (NPs-Fe) were synthesized from rosemary leaf extracts (Rosmarinus officinalis L) in order to create an antibacterial compounds for use as a fruit preservative. By using UV-VIS spectroscopy and phytochemical analysis to analyze NPs-Fe qualitatively and quantitatively, which are revealed an absorption in the 389-418nm regions, which matches the resonance of their surface plasmons. The size and morphology of the NPs-Fe were also determined using scanning electronic microscopy, which revealed a spherical shape with a diameter of 23nm, while the bioactivity exam to shows inhibitory effect against several pathogenic bacteria.