The exact physical modeling for scattered light modulation is critical in phototherapy, biomedical imaging, and free-space optical communications. In particular, the angular spectrum modeling of scattered light has attracted considerable attention, but the existing angular spectrum models neglect the polarization of photons, degrading their performance. Here, we propose a full-polarization angular spectrum model (fpASM) to take the polarization into account. This model involves a combination of the optical field changes and free-space angular spectrum diffraction, and enables an investigation of the influence of polarization-related factors on the performance of scattered light modulation. By establishing the relationship between various model parameters and macroscopic scattering properties, our model can effectively characterize various depolarization conditions. As a demonstration, we apply the model in the time-reversal data transmission and anti-scattering light focusing. Our method allows the analysis of various depolarization scattering events and benefits applications related to scattered light modulation.