Using a Ge-SiO2 (GSO) composite target with the Ge wafer in the target having percentage areas of 0%,5% and 10%,three types of nanometer Ge particles embedded Si oxide films were deposited on p-type Si substrates by the rf magnetron sputtering technique. These samples were annealed in a N2 atmosphere at 300,600,800 or 900℃ for 30min.From Raman scattering spectra,we obtained the sizes of nanometer Ge particles which increase with increasing percentage area of the Ge wafer in the sputtering target.From the fitting of Raman scattering spectra,average diameters of nanometer Ge particles in the GSO(5%) sample increase from 5.4 to 9.5nm with annealing temperature increasing from 600 to 900℃. The peak with energy around 2.1eV exists in the photoluminescence spectra of all the different sizes of nanometer Ge particles embedded silicon oxide samples.The photoluminescence spectrum of the silicon oxide film prepared using a pure SiO2 target has other two peaks with light emission energies around 1.9 and 2.3eV respectively. The experimental facts are inconsistent with the predication of the quantum confinement model,but can be explained by the quantum confinement/luminescence center model.