In order to obtain the loading characteristics of magnetic particle brake (MPB) in rotary system, the servo-motor controlling and testing experimental platform is used to research MPB loading characteristics. The key step is designing different experiments that include static loading experiment, step loading experiment, and tracking loading experiment. Based on the static experiment data, the MPB static property presents hysteresis which is described appropriately in the way of piecewise fitting. The response time in step experiment is longer in upward section than in downward section and it has no relation with the speed of MPB by lucubrating step experiment data. Phase difference is relevant to input current excitation frequency after analyzing tracking experiment data. The loading characteristic of MPB is closely relation to the MPB velocity which is proposed in rotary loading system. When the input current doesn’t change, the output torque increases along with the rotary speed increasing. Also, this paper provides reference materials for improving the loading precision, mathematics modeling, and hysteresis compensation.