Abstract: The output of mirror-image is not allowed for an OE-HOE winal optical system. The similarity of image spare to object space is required. This paper studies optical features of reflective phase HOE and the transformation of object-image coordinates. Finally, it presents the designing principle of the similarity of image space to Object space in the holographic single-tube night vision optical system of goggles-set and in the optical system of holographic head-up display.