The primary goal of this study is to use the Drude model to analyze the influence of shape and size on the plasmon resonance peak of gold nanoparticles and quality factor of gold based on dielectric function. Depending on the shape of the gold nanoparticles, the effect will either get worse or get better. The value of the dielectric function of gold nanoparticles shifts away from or toward the bulk dielectric function as size rises, and vice versa. Significant variation in plasmon resonance peak of gold was observed when the particle size becomes smaller than 100 nm. The nanoparticles can be defined as particle having sizes between 1-100 nm in agreement with the definition reported in literature. The imaginary part of a gold nanoparticle's dielectric function mostly depends on size, while the real part depends on the frequency of the incident light. The greatest extinction occurs when the real part of the dielectric function is equal to the dielectric function of the surrounding medium, while for smaller nanoparticles, the resonance of the extinction cross-section is due to absorption. Since, gold showed minimum quality factor in infrared regions while for silver showed maximum in visible and near infrared. Therefore, Plasmon nanoparticles cause strong electromagnetic fields to form on the particle surface, which amplifies all radiative characteristics including absorption and scattering, used as key plasmonic application. When the frequency of electromagnetic wave (EMW) coincides with the frequency of electron oscillation, then the plasmon resonance peak would create. We have seen that, effect of shape and size on the plasmon resonance of gold nanoparticles as well as all particle sizes of silver showed higher quality factor compare to gold but in the future researcher will investigate the environmental surrounding effect of nanoparticles and Compare the optical properties of both gold and silver nanoparticles with different sizes after synthesized their nanoparticles.