A superconducting magnet for eddy-current braking for a high-speed train. The superconducting magnet is fixed at a bottom of a bogie of the high-speed train through a connecting mechanism, and an air gap is formed between the superconducting magnet and a top of a guide rail below the bogie. The superconducting magnet after being excited generates an eddy-current effect with the guide rail of the high-speed train, so as to generate a braking force opposite to a traveling direction of the train, thereby braking the high-speed train. A liquid-level meter is provided on the superconducting magnet to detect a position of a cooling agent liquid level in real time. The superconducting magnet withstands vibration impact through elastic tie rod assemblies when the high-speed train is under operation, showing good adaptability.