An outer-rotor permanent magnet brushless motor is disclosed, which comprises an outer-rotor and an inner-stator. The outer-rotor configured with P poles, P is a natural number and denotes a multiple of 4. The inner-stator has a stator axle, and S teeth which configured on outer surface of stator, S=P−1, S is a natural number. A circle is formed about a center of the stator axle from the center of the outer end surface. A correction angle a1 and an original angle a are defined from the center of the outer end surface. T The ratio of a1/a is defined by the following formula: 0.2