The utility model discloses a series reactor protection device comprising a switch power source, a MCU processing circuit, a bus PT used for collecting a voltage value of a bus connected with a series reactor, a discharge PT used for collecting a voltage value of a shunt capacitor, and a current transformer used for collecting a current value of the bus. The output ends of the bus PT, the discharge PT and the current transformer are connected with an analog signal conversion circuit. The output end of the analog signal conversion circuit is connected with the input end of the MCU processing circuit. The output end of the MCU processing circuit is connected with a switching switch of the series reactor through an on-off output circuit. The device solves the problem related to safe operation of a series reactor in a conventional shunt capacitor compensation device, solves the short circuit problem of a winding wire compartment in the series reactor, and solves the problems of turn-to-turn short circuit and layer short circuit of the series reactor, thereby guaranteeing safe operation of the series reactor.