A single phase line switch having a phase line input connected to a phase line of the electric network and a phase line output connected to a negative line of the electric network via resistive loads or capacitive loads. The single phase line includes a first power supply unit connected between the phase line input and the phase line output, a second power supply unit, a controlled switch configured to control the second power unit to be on or off, and a micro control unit (MCU) configured to control the controlled switch to be switched on or off. The first power supply unit is configured to provide a power supply to the MCU when the controlled switch is off. The second power unit is configured to provide a power supply to the MCU and the controlled switch when the controlled switch is on, the second power supply unit being serially connected with the controlled switch, the second power supply and the controlled switch being parallel connected with the first power supply unit. The first power supply unit and the second power supply unit each comprises a voltage output terminal connected to a power supply end of the MCU.