The stator magnetic flux barriers can effectively suppress the magnetomotive force (MMF) harmonics of the fractional slot concentrated winding, thus reducing the loss, noise and vibration of the motor. In this paper, the position and width of the magnetic flux barriers are optimized to improve the output torque and efficiency by changing the spatial harmonic component ratio of the stator windings in the magnetic field. The influence of the position and width of the stator magnetic flux barriers on the stator magnetomotive force, winding factor, no-load characteristics and load characteristics of 12-slot/14-pole (Ns<2p) and 12-slot/10-pole (Ns>2p) motors are analyzed by using the finite element method. The results show that for 12-slot/14-pole motor, the appropriate width of the stator auxiliary tooth magnetic flux barriers can increase the magnetic accumulation effect and winding factor of the motor, and reduce the non-working MMF harmonics, so as to improve the electromagnetic performance of the motors significantly. For 12-slot/10-pole motor, the appropriate width of the stator armature tooth magnetic flux barriers can increase the magnetic accumulation effect and winding factor of the motor, and reduce the non-working MF harmonics, so as to significantly improve the electromagnetic performance of the motor. Finally, the correctness of the finite element analysis results is verified by experiments on prototypes.