In recent years, permanent magnet synchronous motor (PMSM) has attracted extensive attention because of its high efficiency in the field of rail transit. According to the characteristics of the rail transit traction system, combined with the mathematical model of PMSM, central 60 degree modulation and selective harmonic elimination PWM (SHEPWM) are analyzed theoretically. The strategy of harmonic current and torque harmonic characteristics were compared, the advantages and disadvantages of the SHEPWM 0–60°, SHEPWM 0–90° and central 60 degree modulation were analyzed. Finally, through experiment on a 180 kW PMSM, the correctness of the theoretical analysis is verified.