The invention discloses an automobile head-up display system and method. The automobile head-up display system comprises front windshield glass, a liquid crystal thin film, a driving power supply and a projection ray machine, wherein the liquid crystal thin film is laminated on the surface of the front windshield glass; the liquid crystal thin film comprises a plurality of light dimming regions; the driving power supply is used for providing independent driving electric fields to the plurality of light dimming regions respectively; and the projection ray machine is provided with an adjustable projection emission hole and the projection emission hole is arranged toward the liquid crystal thin film. With the adoption of the automobile head-up display system and method provided by the invention, the liquid crystal thin film comprising the plurality of light dimming regions is arranged on the front windshield glass, so that images emitted by the projection ray machine are reflected into a visible range of a driver through the light dimming regions and the driver can observe readings of an instrument panel without lowering the head, so that the head-up display effect is realized.