Provided is an automatic lamplight controller. The automatic lamplight controller comprises a control circuit, a photosensitive sensor, a lamplight sensor, a triaxial acceleration sensor U3, a car speed signal, combined lamplight signals, a driving circuit, low beam lamps, high beam lamps and the like. The control circuit comprises an external power supply input circuit connected with the input end of a single chip microcomputer U4, a crystal oscillation circuit and a program download interface circuit. The output ends of the photosensitive sensor, the lamplight sensor, the car speed signal, and the combined lamplight signals are connected with the input end of the single chip microcomputer U4. The output end of the triaxial acceleration sensor U3 is connected with an SPI interface of the single chip microcomputer. The output end of the control circuit is connected with the low beam lamps and the high beam lamps through the driving circuit. According to the changes in the intensity of ambient light, headlamps of a car are automatically controlled to be lightened or turned off, the potential safety hazards caused by frequent light changing or no light changing to the safe driving are prevented, and the safety of night driving is guaranteed.