Abstract This paper examined the optical properties of Gold nanoparticles. The unique properties of gold nanoparticles has determined by size ,shape and refractive index have stimulated and increasing interest in the application of Gold nanoparticles in many application Such as diagnostics and therapeutics , biosensor, photo acoustic image and solar cell. Their uniqueness arises from their size, shape, and dielectric environment. The optical properties of Gold nanoparticles provide wide range of construction optical biosensors. The excellent biocompatibility, conductivity, catalytic properties, high surface-to-volume ratio and high density of Gold nanoparticles facilitate extensive application of Gold nanoparticles in construction of electrochemical and piezoelectric biosensors with enhanced analytical performance. This study assesses the optical properties of gold nanoparticles based on several researcher and published works.