Nowadays, we need to develop eco-friendly nanoparticles synthesis process that does not use toxic chemicals in the synthesis methods. Biological synthesis of nanomaterials is cheaper, innovative and environmental friendly. From this point, the present study focused on the synthesis of silver nanoparticles from the extracts of Ulva lactuca, Sargassum denticulatum, Spirulina platensis and Chlorella vulgaris. Characterizations were performed by UV-Visible Spectroscopy (UV-Vis), X-ray Diffraction (XRD) and particle morphology, and size of silver nanoparticles were observed by transmission electron microscope (TEM) It was found spherical shaped nanoparticles sizes with average diameter of approximately 20,78.8, 31 and 50 nm from the extracts  of the four algal species (Ulva lactuca, Sargassum denticulatum, Chlorella vulgaris and Spirulina platensis), respectively. So, the extracts from algae were screened for phytochemicals analysis followed by FT-IR to know the present chemical functional groups. Therefore, the present study illustrates silver nanoparticles can play an influential role in nanobiotechnology field in future.