Abstract: A system for use in imaging in the air, including: an image source, a transflective mirror and a retroreflective element. Light emitted by the image source is irradiated onto the retroreflective element after being reflected by the transflective mirror, the light is reflected on the retroreflective element and emerges in an opposite direction along an original incident path, and after being transmitted by the transflective mirror, then forms a real image. A selective transmissive film is provided on a side of the transflective mirror facing the image source, and a phase delay optical element is provided on a side of the retroreflective element facing the transflective mirror such that first linearly polarized light incident on the retroreflective element from the transflective mirror becomes circularly polarized light after passing through the phase delay optical element.