Disclosed are a display device and an operation method thereof. The display device includes a primary display screen, a secondary display and an optical function processor. The primary display screen has a display surface and includes a transparent region; the secondary display is located at a side of the primary display screen opposite to the display surface of the primary display screen, and is configured to project image light to the transparent region of the primary display screen for displaying in the transparent region; the optical function processor is located at the side of the primary display screen opposite to the display surface of the primary display screen, and is configured to perform the corresponding operation.