The application provides a power supply system for a parallel smart battery module. The power supply system comprises a parallel smart battery module set, a feeder switch and an auxiliary capacitor, wherein the input end of the parallel smart battery module set is connected with a power grid; the output end of the parallel smart battery module set is connected with a feeder branch; one end of the feeder switch is connected with the feeder branch; the other end of the feeder switch is connected with a load; one end of the auxiliary capacitor is connected with the feeder branch; the other end of the auxiliary capacitor is grounded; and the auxiliary capacitor is used for providing failure currents capable of ensuring tripping of the feeder switch when the parallel smart battery module set has no output currents. When the short circuit occurs in the feeder branch to cause cut-off of supply of the parallel smart battery module set and the feeder switch still does not trip, the auxiliary capacitor can provide the failure currents to the feeder branch, as a result, the fact that the feeder switch can normally trip under the condition of not being powered by the parallel smart battery module set is ensured.