The invention provides a magnetic control type controllable shunt reactor, which comprises a body and an excitation system, wherein the body is of a three-winding structure and comprises a high-voltage side winding, a control winding and a compensation winding; the excitation system comprises a self-excitation system provided with an alternating current side connected with the compensation windingand an external excitation system connected with a station power supply, the excitation system further comprises a rectifier output protection module, and the rectifier output protection module is connected with a direct current bus of the rectifier output; and the rectifier output protection module comprises a balancing resistor, a measuring resistor and a lightning arrester. The technical scheme provided by the invention can ensure the safety of rectifying equipment, so that electrical equipment are avoided from being damaged by overvoltage at the rectifier output side during a failure or impact, the operation reliability and safety of the magnetic control type controllable shunt reactor are improved, and the magnetic control type controllable shunt reactor is guaranteed to play a roleof reactive power balancing and voltage stabilizing in the system.