By recording the polarization grating formed by the interference of two polarized lights, polarization holography can store the information in polarization sensitive materials. In contrast to traditional holography, polarization holography owns many unique properties, for instance, utilizing the long-neglected polarization information and increasing storage capacity. This paper first briefly introduced the development of polarization holography, the tensor-based holographic theory and some of its inferences. Then the further applications of polarization holography in high density data storage are briefly overviewed.