A diffraction grating recording medium including a waveguide layer and a grating structure layer is provided. The waveguide layer has a reflective surface and a light incident surface, in which a thickness of the waveguide layer is between 100 nanometers and 2 micrometers, and the reflective surface reflects a light that enters the waveguide layer from the light incident layer. The grating structure layer is disposed on the light incident surface of the waveguide layer, in which the grating structure layer has a plurality of diffractive elements, and the arranging period of the diffractive elements is between 50 nanometers and 900 nanometers.