In this study, we synthesized silver nanoparticles (Ag- NPs) using fruit aqueous extract of Psidium guajava (PG). PG fruits were used to prepare the aqueous extract for this study. According to this method, including potential environmental pollution problems and the complexity of the synthesis, in this study, the feasibility of using the fruits extract of Psidium guajava (PG) for the reduction of silver ions to nanoparticles form have been studied. Silver nanoparticles were characterized with different techniques such as UV–vis spectroscopy, X-ray diffraction (XRD), Scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Transmission electron microscopy experiments showed that these nanoparticles are spherical and uniformly distributed and its size is from 15 to 40 nm. X-ray diffraction pattern showed high purity and face centered cubic structure of gold nanoparticles with size of 25nm The scanning electron microscopy (SEM) implies the right o forming silver nanoparticles. The results, confirm that silver nanoparticles have synthesized by the fruits extract of Psidium guajava (PG).