It is found silver nanoparticles have strong antibacterial activity due to use in medical applications. It can be tuned antibacterial activity through control the shape and size of the synthesized silver nanoparticles. This article, silver nanoparticles were produced as different sizes at different reaction temperatures by chemical reaction method. Morphology and structure have been characterized by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-ray diffraction (XRD) and UV-Visible Spectroscopy. Results indicate that silver nanoparticles have different sizes in range of (30- 97.26 nm). Additionally, antibacterial activity test against the pathogens, namely Escherichia colis hows effective inhibitory activity.