The present invention provides an ultra-thin optical component, including a mirror projection device and a reflector, where the mirror projection device is configured to refract image light symmetrically, then form a real image, and project the real image to the reflector, where the real image is located between a human eye and the reflector; and the reflector is configured to reflect the image light to the human eye. The present invention further provides a display device using the ultra-thin optical component and a virtual imaging method. By means of the ultra-thin optical component, the display device, and the imaging method in the present invention, an optical component is made thinner and lighter, and an image source display device is easier to configure and package, to achieve the appearance of ordinary glasses.