Given that plant leaves correspond to strong scattering media, a self-built Stokes polarization imaging system is used in this study to accurately describe the scattering characteristics of leaves. By further calculation of Stokes vector of plant leaves, the polarization uniformity of the physical quantity is used to systematically examine their polarization characteristics: 1) the polarization characteristics of circularly polarized light and linearly polarized light on plant leaves are investigated, and it is determined that the polarization uniformity of leaves is higher under the incidence of linearly polarized light when compared to circularly polarized light; 2) the dependence between the angle of leaf vein and direction of polarized light is examined, and it is determined that when the direction of linear polarized light is perpendicular to the angle direction of leaf vein, the polarization uniformity of leaf vein is the highest; 3) the relationship between depolarization parameters and leaf water content is obtained. It is observed that as the leaf water content gradually decreases, the polarization uniformity of the leaf correspondingly increases. By examining the interaction between polarized light and plant leaves, this study demonstrates that polarization uniformity is a significant descriptor of leaf depolarization characteristics in response to polarized light. This insight lays a foundation for subsequent research into plant microstructure and growth state.