According to the special rotor structure of permanent magnet toroidal motor (PMTM), an electromagnetic parameter equation of the motor is established. The time varying mathematical model with the rotor position information of planetary gear is derived. The periodic fluctuation characteristics of PMTM are analyzed by using the statespace method. In combination with the timevarying parameters of PMTM, the setting parameter of PI controller is made. In combination with the parameter perturbation caused by the rotation of planetary wheel, the rotor position information obtained from the closedloop system feedback is introduced into the terminal sliding mode controller, enabling terminal sliding mode control parameters to track the timevarying parameters of toroidal motor. The simulation results of terminal sliding mode control and PI control are compared and analyzed, and the results show that the terminal sliding mode control strategy weakens effectively the fluctuation amplitude of output torque of PMTM, and is good at response speed, in interference immunity, and in robustness.