Gold nanoparticles (Au NPs) have been attracting more attention because they have many color varieties in the visible region based on plasmon resonance, which is due to the collective oscillation of the electrons at the surface of the nanoparticles. We prepared 6 nm Au NPs to modify the surface of the glass substrate. Surface plasmons resonance of Au NPs in toluene is between 500 nm and 600 nm. When Au NPs are modified on the glass substrate, the peak of surface plasmons resonance of Au NPs is shifted. We employed spectral ellipsometry to detect optical properties. Then the characteristics of surface plasmons resonance of Au NPs is determined by reflective index. The performance of surface plasmons resonance of Au NPs on the glass substrate is simulated and shown.