The utility model discloses a PLC-based power supply emergency switching device for a transformer station. The PLC-based power supply emergency switching device comprises a programmable controller, and bus detection circuits, an inlet wire power supply detection circuit, circuit breaker control circuits, circuit breaker position signal acquisition circuits, circuit breaker control intermediate relay circuits, circuit breaker switching-closing indicating circuits and an emergency switching action reset circuit which are respectively connected with the programmable controller, and circuit breaker circuits connected with the circuit breaker control intermediate relay circuits. According to the PLC-based power supply emergency switching device for the transformer station, the defects of high failure rate, low reliability and poor security and the like in the prior art can be overcome, and the advantages of low failure rate, high reliability and good security can be achieved.