This paper proposes a road driving warning device, including support rods and warning plates. Several display screens are installed on one side of the warning panel. Indication light balls are set on the display screen. Warning board top fixed connection with top box. Several radar detectors are mounted on one side of the roof box. Several radar detectors correspond to several display screens. Several warning lights are installed on the top of the top box. Several warning lights correspond to several radar detectors. The sliding side of the support rod cleans the unit. Control of the position change of several indicator light balls on the corresponding display screen by several radar detectors, so that the driver can get the specific driving situation of the road section by observing several display screens and indicating the light ball. Preparation for lane change overtaking, grasp the location information and speed of all vehicles in this section in advance.