An on-board head-up display device includes: a navigation module, an eye position detecting module, an image processing module and an image display module; the navigation module is configured to input navigation data and a spatial position coordinate of a car with respect to a position where navigation data is to be executed, to the image processing module; the eye position detecting module is configured to detect a spatial position coordinate of the left and right eyes of the driver with respect to the car; the image processing module is configured to form display information; and the image displaying module, configured to display the display information in image in front of the eyes of the driver, and the image is on a line between the eyes of the driver and the position where the navigation information to be executed.