Headlight is an important equipment for the driver to provide road lighting for drivers at night or under low visibility. It is also a light signal device for drivers to send out warning and contact. Therefore, headlamps must have sufficient luminous intensity and correct direction of illumination. In the course of driving, it may cause the change of the installation position of the headlamp components after the vibration of the car, which will change the correct direction of the beam. At the same time, the light bulb will gradually aging in the process of use, and the reflector will be polluted to make the light gathering performance worse, which leads to the insufficient brightness of the headlights, which changes these changes. All of them will cause drivers to identify unclear roads ahead, or to cause the other drivers to blink when crossing cars with opposite cars. Thus the occurrence of the accident. Therefore, the luminous intensity of the headlamp and the direction of the beam illumination are listed as the necessary items for vehicle operation safety inspection. Headlamp detector has 4 types: spotlight, screen type, automatic tracking optical axis type and projection type.