Magnetic hysteresis yarn tensioner is a new-type component which is used in textile machinery for achieving automatic controlling. Its hysteresis damping characteristics of the torque is directly related to changes in the tension of the yarn. Hysteresis damping torque characteristics depends on the excitation voltage of the yarn tension and the magnetic storage of the hysteresis loop. In this paper, electromagnetic properties of the key components in the magnetic t hysteresis yarn tension were analyzed, and the outputting characteristics of magnetic hysteresis yarn hysteresis damping torque in different excitation voltage and speed had been obtained. The theoretical and experimental foundation of is provided about improving the uniformity of textile yarn and achieving the group control technology of Yarn tension.