Single-phase asynchronous motor is widely and irreplaceable in the place of single-phase power supply. However, the single-phase asynchronous motor also has some problems, such as low efficiency and power factor, large amount of materials, large vibration and noise. The design and research of double capacitance single-phase asynchronous motor is carried out to improve the energy efficiency, and the working principle of the motor is analyzed. Taking YL801-2 motor as an example, the stator and rotor punching plates are selected according to the frame number, and the scheme selection and efficiency optimization design are carried out for the stator winding and slot size. The input current, output torque, efficiency, locked torque/locked current and other performance of indicators under rated and starting conditions are calculated by field circuit coupling finite element method. The results show that the performance reach the level II energy efficiency requirements of GB 18613—2020 and the technical requirements of JB/T 7588—2010. The design can be used for references to further improve the energy efficiency of single-phase asynchronous motors.