In this paper, a new magnetic equivalent circuit model is proposed to calculate the torque and eddy current loss of slotted disc permanent magnet eddy current coupler. The conductor disc guide rod is innovatively compared with the guide rod of a squirrel cage motor. The expression of eddy current loss and torque is obtained by dividing the flux path in the slotted conductor disc into several branches and combining with the traditional equivalent magnetic circuit method. After calculating the torque and eddy current loss by this method, NSGA-II algorithm is used to optimize the structural parameters of the slotted disc permanent magnet eddy current coupler, so as to improve the performance of the coupler. Finally, the optimization results are compared with those calculated by three-dimensional finite element method. The results show that under the condition of low slip velocity, the method is effective.