Stimulated Raman scattering(SRS) of binary solution of toluene and m-xylene are studied at different volume concentrations in liquid-core optical fiber. The experimental results show that the vibration modes of 1002 cm-1, 2920 cm-1 and 3058 cm-1 bands are simultaneously stimulated to generate the SRS, and the SRS thresholds of the 1st-order Stokes of 2920 cm-1 and 3058 cm-1 bands are lowered compared with the 2nd-order Stokes of 1002 cm-1 band, and the main peaks of 2920 cm-1 and 3058 cm-1 bands are different as volume concentration changes. We assume that the intermolecular Fermi resonance is the main mechanism for these phenomena, which is explained by the Raman scattering cross section theory.