A rear car overtaking reminding system based on distance measuring is mainly composed of a distance measuring system, an overtaking identification system and an overtaking reminding system. The distance measuring system measures the distance between the left adjacent lane and a car, the distance between the right adjacent lane and the car and the distance between a car behind the lane where the car is located and the car; the overtaking identification system judges an overtaking intention of the rear car according to distance change information of the adjacent moments and the safety distance; the overtaking reminding system drives corresponding overtaking indicator lights and can give out voice prompt to remind a driver that the rear car is about to overtake from the left side or the right side according to the overtaking intention. By means of the rear car overtaking reminding system based on distance measuring, it can be guaranteed that the driver perceives approaching of the rear car and the overtaking intention of the rear car, the condition that lane changing is conducted when the rear car overtakes is avoided, and safe driving of the car is guaranteed.