The invention relates to an automatic headlamp adjustment system for a rail train. The automatic headlamp adjustment system comprises a headlamp arranged at the top of the rail train, a pressure sensor arranged under a seat in the rail train, and a light source drive system connected with the headlamp and the pressure sensor, wherein the light source drive system is used for controlling the headlamp to be turned off or controlling the headlamp to be in a low-power-consumption state when it is detected that the output voltage of the pressure sensor is smaller than a threshold voltage and is maintained for a threshold time or longer. The headlamp of the rail train is adaptively controlled by detecting the state on the seat, the energy consumption is reduced, and automatic management is achieved.