The present study describes the role of cellular pigments in the biosynthesis of silver nanoparticles. The use of algae for nanoparticle synthesis has advantages such as being fast, eco-friendly, biocompatible, and non-toxic chemicals. However, it takes place in a shorter time and with lower cost than other biosynthesis methods. In this study, we synthesized silver nanoparticle intracellularly from 5 mM AgNO3 solution-mediated Desmodesmus sp. as reducing agent. The successful synthesis of silver nanoparticles was confirmed by UV-Vis, TEM, XRD and confocal analysis. It was observed that the algal cells synthesized under TEM analysis are intact and the nanoparticles accumulate in the compact inner region of the cells without forming aggregates. In the UV-Vis spectroscopy analysis, nanoparticle synthesis was performed in the first 24 h, which was confirmed by the reduction of chlorophyll content. In addition, this situation was seen in confocal microscopy analysis due to the autofluorescence of the Desmodesmus sp.