This invention relates to a brushless dual-rotor motor composed of an inner motor of an axial magnet circuit structure and an outer motor of excitation circuit structure, in which, the inner motor is composed of an input shaft, an inner rotor core, an inner magnet alnico of an inner rotor, an outer rotor core and an inner winding of an outer rotor, the outer rotor is composed of a stator winding, a stator core, an outer rotor core and an outer winding of the outer rotor, which are placed in the following sequence from inside: the input shaft, the inner rotor core, the magnet alnico of the inner rotor, a core of the outer rotor, the inner winding of the outer rotor, the outer winding of the outer rotor, the stator core, the stator winding and the shell, and the core of the inner rotor is fixed on the input shaft and rotates together with it, the stator core is fixed on the shell, the core of the outer rotor is connected with the output shaft rigidly and rotates together with it, the inner winding of the outer rotor and the outer winding of the outer rotor form a circuit.