Power supply capable of opening and closing a DC standby power supply

The present invention provides a power supply capable of opening and closing a DC standby power supply, and the power supply comprises a switchover type power circuit and a relay-driven circuit. One end of an alternating current source input port of the switchover type power circuit connects with a selector switch of a relay in series, and the switchover type power circuit converts an AC power source to a DC standby power supply and at least one DC working power supply when the relay is in a conducting state. The relay-driven circuit controls the relay, the selector switch of the relay is non-conducting when a computer connected to the power supply shuts down and thus the switchover type power circuit does not output the DC standby power supply until the moment of the computer starting, and then the relay-driven circuit conducts the selector switch of the relay to provide the DC standby power supply required by the computer starting.