Abstract: Brushless double-fed machines (BDFM) have received a lot of attention in the field of wind power generation due to their simple structure, high reliability and small inverter capacity, etc. The slot ratio of the stator and rotor has a certain degree of influence on the motor performance and vibration. In this paper, the magnetic potential of the stator and rotor of a winding brushless double-fed motor is analyzed as a basis to derive the comparison of the electromagnetic force waves of different slot ratios and the effect of slot ratios on the performance of the motor, three options of slot ratios are given to meet the requirements, and the rotor winding harmonics of each option are calculated for analysis and comparison. The finite element method is used to study the load performance of 48/36 slot, 42/36 slot and 36/30 slot solutions under the same requirements. And the electromagnetic force of the stator tooth is derived to analyze and compare the vibration response of the motor. Finally, the prototype is tested to verify the correctness of the finite element simulation. At the same time, the test results also prove that the motor equipped with the selected slot exhibits minimal vibration, low rotor current, high system output voltage and low saturation level.