Blood flow alters the scattering behavior of penetration light, causing instability in the polarization state to emerge at the underlying tissue during polarization-sensitive optical coherence tomography (PSOCT). We propose an eigen decomposition method to meet this challenge, where the static and dynamic scattering signals are separated for PSOCT to provide the polarization measurements of the tissue of interest that is located beneath the blood flow. Using flow phantoms made by Intralipid solution and 3D-printed birefringent material, we show the flow-induced effects on the measurements of sample birefringent properties of optical axis, phase retardation, and degree of polarization uniformity. We demonstrate the usefulness of the proposed method through in vivo imaging of the human nail fold.