Abstract: It is a type of brushless motor with double rotors which is composed of one inside motor with radial-vertical permanent magnetic circuit and one outside motor with magnetic excitation circuit. The inside motor is made up of the input shaft, the inner rotor core, the permanent magnetic steel of the inner rotor, the external rotor core and the inner winding of the external rotor. The outside motor is made up of the stator winding, the stator core, the external rotor core and the external winding of the external rotor. From the inside toward outside, the specific structural arrangement is as follows: the input shaft, the inner rotor, the inner rotor core, the permanent magnetic steel of inner rotor core, the external rotor core, the inner winding of external core, the external winding of external rotor, the stator core, the stator winding and the shell.