A device for resolving common-mode voltage interference is applied to a power supply system including a power converter and a switch mechanism. Each phase of an output end of the power converter is connected to a downstream circuit by using the switch mechanism. The switch mechanism includes a first switch and a second switch. The device includes a controller and a passive component. Two ends of the first switch in at least one phase of the output end of the power converter are connected in parallel to the passive component, and the controller controls the second switch to be turned on, and when a voltage difference between the two ends of the first switch is less than a preset voltage, controls the first switch to be turned on. In this manner, the switch mechanism is protected, thereby prolonging a service life of the switch mechanism.