Aiming at the high requirements of the electric pitch servo system of the megawatt high-power wind turbine, combined with the design characteristics of the permanent magnet synchronous servo motor, the field-circuit combination method is used to electromagnetically design the pitch permanent magnet synchronous servo motor through finite element analysis. The software is modeled and simulated, and the genetic algorithm is used to optimize the cogging torque and the volume of the permanent magnet. The electromagnetic optimization scheme is determined. Then according to the scheme prototyped the prototype, the experimental results show that the optimized pitch servo motor meets the performance requirements.