In the paper, a measuring method of the stimulated Raman scattering (SRS) of diffused N2 in solid silica optical fiber is proposed. It is a new type of Raman gain medium-gas in glass. The dependence of threshold and linewidth of SES on the power of pump light is discussed. The output mode is measured when the transmission wavelength in the optical fiber is lower than the cut-off wavelength of the single mode silica optical fiber. In addition a week coupling mode between N2 and SiO2 molecules is observed in the experiment.