In the present paper, the authors analyzed the absorption and scattering effects of changing the solution concentration on the spectra, and dealed with the wavelength, where the absorption and scattering effects counteract completely, the fiducial wavelength method can eliminate the perturbation from shift of instrument and temperature, and also can improve predicting ability of the model. The result of utilizing this method to process the spectral data of two sample sets, i. e. intralipid solution and plasma solution with different level glucose, has verified that fiducial wavelength method can improve correlation coefficient and decrease RMSEP of predicting model.