The transmission characteristics of planetary permanent magnet magnetorheological transmission device were analyzed.The transmission device had a cylindrical working structure and the excitation source was set as a builtin permanent magnet.The device was provided with a magnetic tube set structure that could rotate freely,thus the device output torque ability was enhanced and the transmission was steady and reliable. The influencing factors of the output torque of the magnetorheological transmission device were analyzed through building model.A prototype of the magnetorheological transmission device was developed,and the speed and torque characteristics of the prototype were tested. The results show that the device can effectively transmit torque, effectively adjust the slip speed, and adjust the output speed by controlling the strength of the internal magnetic field.