Dry-type air-core reactors are widely used in power system. They usually operate under high-voltage conditions within harsh working environments. In practical application, short-circuit and open-circuit faults in the inter-turn windings are the main fault types for reactors. Considering the problems of delayed warning, low sensitivity, as well as misjudgment of faults in the monitoring of dry-type air-core reactors, this paper proposes a dry-type reactor edge fault warning system based on star-arm current detection. This paper first discusses the structure of the edge fault warning system based on star-arm current of dry-type air-core reactor. Then, the software and hardware systems of the edge fault warning system are designed and their working processes are discussed. Finally, the effectiveness of the proposed edge fault warning system in fault identification and monitoring is verified through the analysis of inter-turn short-circuit and winding open-circuit experiments of dry-type air-core reactor.