Layered materials are categorized into isotropic layered materials (ILM) and anisotropic layered materials (ALM), distinguished by their in-plane symmetry. ALM exhibit considerable potential in polarized light detectors, field-effect transistors, and thermoelectric devices, attributed to their polarization-sensitive optical response and anisotropic physical properties. Notable examples of ALM, such as black phosphorus (BP), Td-WTe2, ReS2, and ReSe2, have garnered significant attention. During the growth, assembly, or post-regulation processes of materials, ILM can transform into ALM due to in-plane symmetry breaking, making ALM the predominant form among layered materials. Consequently, a thorough investigation into the intrinsic optical anisotropy of ALM, as well as the anisotropy of its photon-electron and electron-phonon coupling, is essential for advancing its application in polarized optoelectronic devices.