Standby power supply switching device and power supply system

The utility model provides a standby power supply switching device and a power supply system. The switching device comprises a relay, a low-voltage power supply, a detection circuit, a controller and a switch control circuit. The detection circuit is used for detecting a current state parameter of the standby power supply; the controller is used for controlling the switch-on or switch-off of the switch control circuit according to the current state parameter, the power utilization peak period or the power utilization valley period; the relay is used for controlling the input state of the mains supply according to the connection or disconnection of the switch control circuit; according to the utility model, the problems of resource waste and high use cost of the lithium battery standby power supply in the prior art are solved, the standby power supply supplies power to the external UPS by cutting off the commercial power in the peak period of power utilization, and the commercial power is recovered to supply p