In a power circuit for reducing standby power consumption, a power supply is defined to include a primary power system and a stationary power system. The stationary power system outputs a stationary power after obtaining an input power. A control unit controls ON/OFF of the primary power system, obtains the stationary power as the required power, and receives a PS ON/OFF signal for triggering the control unit, so that the control unit controls the primary power system to supply a primary output power. The power supply includes a switch unit having two ends connected to a power circuit for outputting the stationary power and a virtual load respectively. The PS ON/OFF signal is provided for controlling the switch unit. If the switch unit does not receive the PS ON/OFF signal, it is OFF in a standby mode to avoid unnecessary power consumption of the virtual load.