The invention discloses a vehicle-mounted light supplementing system, which comprises two infrared light supplementing lamps, a drive power supply, an aluminum base plate, a heat radiator and an infrared night-vision camera. The infrared light supplementing lamps are arranged nearby an automobile fog lamp and comprise a plurality of serial infrared LEDs (Light Emitting Diodes) and lenses covering the plurality of infrared LEDs, the plurality of infrared LEDs are connected on one side of the aluminum base plate, the heat radiator is connected on the other side of the aluminum base plate, and the infrared night-vision camera is connected with a vehicle-mounted DVD (Digital Video Disk). Through the structure and the method, the invention has the following advantages that: 1, the infrared light supplementing lamp can irradiate the roads within 150m in order not to influence the sight lines of drivers in a reverse lane, and can not dazzle passengers and the drivers moving in an opposite direction at the same time; and 2, a layered heat radiator can effectively control the temperature of an LED chip in the range of 60-80 DEG C, the change of performances of an infrared LED is easy to restrain, the electric-optical conversion efficiency is improved, and the quick aging and burning of the LED chip are prevented.