Automatic volume adjustment method and device of vehicle-mounted player of bus

The invention discloses an automatic volume adjustment method and device of a vehicle-mounted player of a bus. The automatic volume adjustment method includes the steps that voltage signals between the positive pole and the negative pole of a loudspeaker of a bus-stop reporter are collected and pre-processed; amplitudes of the pre-processed voltage signals are compared with voltage threshold values at a time interval, and a corresponding adjustment instruction is formed according to a comparison result; the volume of the vehicle-mounted player is adjusted according to the adjustment instruction. Compared with a loudspeaker sound signal collecting method in the prior art, the voltage signals between the positive pole and the negative pole of the loudspeaker are collected, the adjustment instruction is generated according to the voltage signals, interference of external sounds is effectively removed, and adjustment precision is improved; additionally, electrical signals are directly collected, conversion from the voltage signals to the sound signals and from the sound signals to the electrical signals in the prior art is avoided, adjustment time delay is reduced and adjustment real-time performance is guaranteed.