A power supply system having a power supply cut-off function in an emergency is provided. The present system includes a power supply device for receiving and supplying external input power to a device for power supply, a remote controller for controlling an operation of the power supply device according to a remote control signal from a remote place, an uninterruptible power supply device for supplying operation power to the remote controller, a first line switch for, when a power switch is turned on, supplying the external input power to the power supply device and the uninterruptible power supply device, and a second line switch disposed between the power supply device and the first line switch and cutting off the external input power supplied to the power supply device via the first line switch when the uninterruptible power supply device does not output the power. According to the present invention, even when the remote controller is out of order in the emergency, the power supply of the power supply device can be cut off using the interrupted power supply device to thus enhance stability and reliability of the equipment.