The synthesis of metal nanoparticles by eco-friendly procedures is a need of nanotechnology today. One such important approach which shows enormous potential is based on the in situ synthesis of gold nanoparticles (AuNPs) using silk fibroin (SF) extracted from Bombyx mori silk. The UV-visible absorption spectra confirmed the reduction of gold ions to gold nanoparticles by showing characteristic surface Plasmon resonance (SPR) in the wavelength range λ = 530-545 nm. The X-ray diffraction (XRD) measurement study suggests the synthesized metal gold nanoparticles are FCC crystal structure. Further, the transmission electron microscopy (TEM) images showed that the formed AuNPs are spherical, rod, hexagonal and triangle in shapes.