A head-up display system includes a display unit and a reflective element. The display unit having a first and a second display areas includes a display panel, a first light source module, and a second light source module. The display panel has a first and a second pixel areas. The first and the second light source modules respectively provide a first and a second light sources. The first light source corresponds to the first pixel area to make the first display area display a first image frame. The second light source corresponds to the second pixel area to make the second display area display a second image frame. The reflective element is located on a transmission path of the first image frame and not located on a transmission path of the second image frame, and reflects the first image frame from the first display area to a target element.