In the observation of multi-angle polarized reflective spectra of objects, in addition to the physical and chemical properties of soil self, the angle factors such as polarization angle, detection zenith angle and so on will have significant impact on the spectra of objects too. Through the introduction of structural equation model (SEM), the multi-source spectral analysis including polarization, multi-angle and hyperspectral technologies is made for the saline alkali soil in western Jilin under the influence of multiple factors. It is found that the impact strength of the geometry factor is greater than that of the nature (salinity) of soil self. The orthogonal tests of three factors and two levels are designed and analyzed. The results also show that the impact of the angle factor is more significant. That is, in the analysis of single factor, the impact of polarization angle and detection zenith angle on the measured spectra is greater than that of the salinity of soil self. Furthermore, the interaction of different factors will have a certain impact on the spectral characteristics too. The SEM is compared with the orthogonal test. The difference and advantages of these two methods in spectral analysis are obtained.