The present invention discloses a station door insulation monitoring and automatic rail connection control device and a control method, the control device comprising: a current sensor, a first contactor, a second contactor, a thyristor, a relay, a voltage-reducing module, a sampling resistor, and a control module; a steel rail is connected to the station door through the current sensor, the first contactor, the voltage-reducing module, and the steel rail in turn; the steel rail is connected to the station door through the current sensor, the second contactor, and the steel rail is connected to the station door through the current sensor, the second contactor; The rail is connected to the station door through a current sensor and a thyristor; the rail is connected to the station door in turn through a current sensor, a relay, and a sampling resistor; the control module is connected to the current sensor; the control module is connected to the two ends of the sampling resistor; and the control module is connected to the first contactor, the second contactor, the thyristor, and the relay, respectively. The present invention is provided with a voltage-reducing module to limit the voltage difference between the vehicle body and the platform door to that first safe voltage of the human body, to ensure the safety of passengers in the process of boarding and alighting the vehicle.