The invention provides a device which uses a controllable high-voltage shunt reactor to inhibit sub-synchronous resonance of a power system and can solve the sub-synchronous resonance problem by a method that a sub-synchronous resonance inhibition module based on the rotation speed measurement of a unit shafting is added in a controller of the controllable high-voltage shunt reactor. The basic structure of the device comprises three parts: a shaft rotation speed measurement system (comprising a shaft rotation speed sensor and a signal processing and transmitting part), an inhibition control system concerning the sub-synchronous resonance and a controllable high-voltage shunt reactor device. The validity of the device is validated by the numerical simulation to a certain planning system.