The invention discloses a method for detection of superconducting magnet quench by using a radio-frequency wave technology, wherein the method comprises a to-be-detected inductor, a balun, an isolating annular assembly, a power source, a cancellation processing part and a detection closed loop system; an external-connection instrument way is adopted, and a superconducting magnet quench phenomenon is diagnosed by a microwave transmission line traveling wave detection technology, so a flexible-configuration and external-connection backup detection means is provided and makes up the shortage of conventional means or is used as an emergency device. A device is mainly composed of four parts: a high-stability power source, the isolated annular assembly, a balanced-unbalanced transformation balun, a receiving and detecting closed loop and the like. The to-be-detected inductor is placed in a dewar, a coil is subjected to balun transformation, and a load impedance is transformed from 0+j(infinity) at a dewar outlet to near 0+j0. By designing different balun impedance transformers, the characteristic impedance of a transmission line becomes adjustable.