Anisotropic persistent spectral holes with more than 400% of depth were written in and read out on frequency-domain organic optical storage material THP/PMMA using polarizationspectral hole-burning technique. The polarization spectral hole-burning mechanism and anisotropic hole formation process at speed on both theory and experiment are reported in this paper. It shows that the polarization spectral hole-burning technique has a strong potential on the application on frequency-domain optical storage and high resolution spectroscopy in solids.