A lighting system with reduced standby power according to the embodiment includes a main control unit to control a lighting device; a driver to supply the control signal to the lighting device; and an AC-DC converting circuit to supply power to the driver. A method of reducing standby power according to the embodiment includes charging a standby power supply unit with power in a normal mode; checking whether a lighting off signal is transmitted and switching off a lighting, and simultaneously, shutting off the power supplied from the AC-DC converting circuit when the lighting off signal is transmitted; changing an operation mode of a lighting device from a normal mode to a standby mode; checking whether a voltage of the standby power supply unit is less than a predetermined level; and charging the standby power supply unit when the voltage is less than the predetermined level.