The technical scheme adopted by the present disclosure discloses an outer rotor brushless motor, which has a motor housing, a magnet, an end cover and a retainer ring, and a plurality of mounting separators all integrally molded with the motor housing are evenly distributed on the inner wall of the motor housing; between two adjacent mounting separators, a mounting groove is provided for a magnet to be mounted; the magnet is mounted within the mounting groove and is axially limited by means of the end cover and the retainer ring. The outer rotor brushless motor disclosed offers good reliability and high efficiency in assembly.