High-speed permanent magnet micromotor with slotless structure is widely used in testing equipment and medical equipment. However, the production process of slotless motor winding is complicated, and the production process of winding can be simplified by using winding printing technology. At present, existing printing technologies are mostly applied to motors with axial flux using rigid printed circuit board (PCB) as carrier. For high-speed motor with radial flux, rigid PCB can hardly meet the requirement for winding distribution along the circumference. Flexible PCB winding comes into being, but there is no complete design scheme of flexible PCB winding motor at present. Therefore, a high-speed micromotor with flexible PCB winding is designed. In order to solve the problem of unequal winding of flexible PCB winding, an average radius method is proposed and the motor is analyzed by simulation. The results show that the average radius method solve the problem of unequal winding of flexible PCB winding, and the desigred flexible PCB winding motor can meet the techaical requirements of the motor and has good thermal stability.