Nanoparticles have been the subject of researchers due to their unique properties. The importance of nanoparticles in technological fields is related to their adaptable properties. They are synthesized by reducing metal ions to uncharged nanoparticles using reducing agents. However, in recent years there have been several initiatives to develop green technology that uses natural resources instead of hazardous chemicals to produce nanoparticles. In green synthesis, biological methods are used for the synthesis of nanoparticles because biological methods are environmentally friendly, safe, economical, uncomplicated and highly productive. So, in this review we discuss different approaches in nanoparticles’ synthesis and comparative characteristics of nanosilver particles, synthesized by physical, chemical, and biological methods.