An optical sheet suitable for linear polarized light to pass through is provided. The optical sheet includes a substrate and a retardation film. The retardation film herein is located on the substrate and has a plurality of optical axes with different extending directions. The linear polarized light after passing through the retardation film is converted into a plurality of linear polarized light with different polarization directions, wherein the retardation film substantially has a phase retardation of λ/2 at anywhere of the area where the linear polarized light passes through and λ is the wavelength of the linear polarized light. Besides, the present invention also provides a display apparatus, a fabricating method of an optical sheet and a fabricating method of a display apparatus.