HEAD UP DISPLAY SYSTEM AND DISPLAY METHOD OF HEAD UP DISPLAY SYSTEM

A head up display system is provided and includes an image source, an image adjustment device, a controller, and a reflector. The image source is adapted to output an image with an image light traveling in a light path. The image adjustment device is positioned on the light path of the image light, wherein the image adjustment device comprises a liquid crystal panel. The controller is adapted to control the image adjustment device. The reflector is adapted to reflect the image light passing through the image adjustment device to a projection screen. A display method of a head up display system is also provided in the disclosure.