For remote sensing of vegetation, light scattered from canopy is partly polarized, which is the basis data for the polarized remote sensing. Thus, it is significant to perform the field polarization measurement of vegetation canopy using the ground-base instrument. The field polarization measurement data not only contain the physical polarization property of vegetation canopy, but also can be used to match with the polarimetry measurements from airborne and spaceborne sensors. Several previous studies have paid some attentions to the polarization of vegetation canopies, because of some airborne and spaceborne instruments can be used to obtain multi-angular polarized information. However, the investigation about the field measurements is rare. To study the contribution of this polarized light to multi-angular observations of reflectance over vegetation canopy, a hyperspectral bidirectional polarized reflectance data of one type of vegetation canopy acquired over a wide viewing range in field was analyzed in this paper. Then, it was analyzed with respect to basic physical polarized reflectance mechanisms. The impact of angular data sampling and the variation of the polarized spectral reflectance were also analyzed. Furthermore, we compared the modeled polarization from two current polarimetric models with our measured polarization of vegetation canopy at selected wavelength. Analyses showed that all the models were good fitted to the measurements; there was a very small spectral variability of the polarized reflectance of vegetation canopies. The good agreement between polarization measurements and modeled results confirms the ability of models and the accuracy of field experiments. These results, deepening our understanding of the scattering properties of vegetation canopies, suggest that we can model the polarization accurately by all the current polarimetric models; they are valuable for the development of polarized remote sensing applications on earth science and useful for studying the contribution of earth polarization on the atmosphere polarization.