The invention discloses a current-limiting-difference-matching-based relay protection system of a distribution network. The principle of the relay protection system is as follows: current-limiting protection devices are arranged at a transformer substation outgoing breaker and an interconnection switch; when an inter-phase short circuit fault occurs, the current-limiting protection device of the outgoing breaker carries out current limiting quickly and, together with a protection device arranged at a feeder section switch, is used for realizing multi-stage difference relay protection cooperation; if an instantaneous fault occurs, re-closing is carried out for power supply recovery by the primary reclosing function of the current-limiting protection device and the feeder section switch; ifa permanent fault occurs, the current-limiting protection device is arranged at the interconnection switch and thus isolation of a fault region and power supply recovery of a perfect region are realized under the current-limiting condition. Compared with the distribution automation technology, relay protection can be carried out quickly and relay protection operation becomes reliable. The current-limiting-difference-matching-based relay protection system is suitable for an overhead distribution network and a cable distribution network.