Coherent anti-Stokes Raman scattering is a nonlinear coherent four-wave mixing effect. But it is hard to quantitatively spectral analyze material components by detecting coherent signal. In the present paper, the resonant and non-resonant signals of mixture of ethanol and water with different volume ratio were experimentally studied with a single-frequency coherent anti-Stokes Raman scattering spectral method. By analyzing the experimental results, we found that the intensity of resonance signals at frequency 2 876 cm-1 is increased with the increase in volume ratio of ethanol and it is quadratic, but the intensity of non-resonant signal linearly increased with the volume ratio of ethanol. So the non-resonance intensity signal is linear with the concentration of the number of molecules N. Therefore, detecting the non-resonance signal will provide a way for the quantitative spectral analysis of the specific ingredients in the mixture.