Abstract: Dynamic model of 3-DOF spherical motor is a mathematical description of the rotor motion process. In the closed-loop control of spherical motor, it is used to calculate the drive torque required when the rotor moves from the current position to the desired position. Aiming at calculating the driving torque of reluctance spherical motor, a dynamic equation modeling method is proposed. According to the motion characteristics of reluctance spherical motor, the spherical rotor is equivalent to three rotary joints in series. The dynamics equation of reluctance spherical motor is derived based on D-H parameters. Then, the unknown parameters in the equation are identified. The prediction results of the final model agree well with the test data. Finally, the reliability of the model under a specific motion is verified by experiments, which provides a theoretical basis for the drive control of reluctance spherical motor.