The differences in structure and transmission performance of three different working gap shapes of disk-type magnetorheological transmission devices were analyzed based on the influence of magnetorheological fluid working gap shape on the transmission performance of magnetorheological transmission devices.The finite element analysis of the transmission device was carried out by the magnetic field finite element method to optimize the structure and dimensions of the transmission device,and the torque equation of the circular arc type working gap was established,and the torque of the three different shapes of gaps were compared by calculation.The results show that when the current is 3 A,the torques of the magnetorheological fluid of the three shapes are 55.77 N·m,71.40 N·m and 74.73 N·m respectively,and the torques of the serrated working gap and the circular-arc working gap are 1.28 times and 1.34 times of the torques of the planar working gap respectively.