The invention relates to a display device and an epitaxial wafer. The display device is provided with a display substrate, a first sub-pixel unit and a second sub-pixel unit, wherein the first sub-pixel unit is arranged on the display substrate; the first sub-pixel unit has a first luminous area; the second sub-pixel unit is arranged on the display substrate; the second sub-pixel has a second luminous area; the first sub-pixel unit and the second sub-pixel unit are defined as the same color type; the first sub-pixel unit and the second sub-pixel unit are formed from an epitaxial structure of the epitaxial wafer; the first sub-pixel unit and the second sub-pixel unit are transferred to the display substrate after being formed from the epitaxial wafer; and the size of the first luminous areaand the second luminous area is at least associated with a photoluminescence measurement result of the epitaxial wafer.