Train identification method and device

The invention provides a train identification method and device. The train identification method comprises a geomagnetic sensor, a processor, a relay, a shell, a bottom cover, connection terminals and a locking mechanism, wherein the shell and the bottom cover form a closed module; the geomagnetic sensor is used for detecting magnetic field intensity of tracks in a train defense area at the present moment; the processor is respectively connected with the relay and the geomagnetic sensor and used for receiving the magnetic field intensity, and controls the relay to be actuated when the magnetic field intensity is greater than a preset magnetic field intensity; when the relay is actuated, a voltage difference is formed at both ends of a controlled circuit, and a line obstacle automatic identification system identifies the state of a train passing through the train defense area by monitoring the voltage difference; data ports of a detection circuit extend to the outside of the closed module through data communic