In order to investigate mechanical properties of silica glass, cylindrical samples of silica glass was prepared for experiments under very high hydrostatic pressure at room temperature. Based on this, the relationship between the applied pressure and the change of density was established. The Ramam spectroscopic test was also performed on tested glass samples to analyze the densification characteristics from microstructure point of view. The change of density was then plotted as a function of the frequency of Ramam spectra. This relationship was then used to analyze the result of Vickers indentation test on the silica glass. The distribution of density in the sample after the Vickers indentation test is finally obtained.