Abstract: The Sol-Gel technique is used to prepare the Ag-SiO₂ composite nanoparticle film on glass substrate.The SEM,TEM and XRD measurements of the films indicate that the single crystal metal Ag nanoparticles are uniformly embedded into the SiO₂ particles.The Ag-SiO₂ composite nanoparticle films are formed.The optical properties of the Ag-SiO₂ composite nanoparticle films were studied.The results show that there is a surface plasmon resonance(SPR)peak around 430 nm in the optical absorption spectra of Ag-SiO₂ composite nanoparticle films.As the molar ratio of Ag and Si increases,the intensity of SPR peak is gradually enhanced,and a blue shift of the SPR peak occurs.The amount of blue shift is about 30 nm.Furthermore,two photoluminescence(PL)peaks at 330 nm and 375 nm(excitation wavelength is 220 nm)are observed in the PL spectra of the Ag-SiO₂ composite nanoparticle films.In addition,the molar ratio of Ag and Si has a modulation on the two PL peaks.