An important aspect of nanotechnology is the development of reliable methods for the synthesis of nanomaterials in vitro that in view of the size, composition and shape can be controlled. In recent years, with increasing environmental problems, many due to green chemistry and attempts for the synthesis of nanomaterials through the environmental clean methods increased. The use of biological organisms for the clean synthesis of nanomaterials is important. In this article we report the synthesis of silver nanoparticles from silver nitrate solution by extract of black pepper from silver nitrate aqueous solution in various environment pH, 9, 10, 12 and 13. Then crystalline structure, morphology and optical properties of these nanoparticles is presented. Prepared samples have been characterized by X-ray diffraction (XRD), UV-Visible Spectrometer (UV-vis) and Scattering Electron Microscope (SEM).