In order to reduce the cogging torque, improve the motor power output performance, put forward a method of matching pole arc coefficient of the adjacent pole. Used the Maxwell stress tensor method and Fourier decomposition solve the cogging torque analytical model of the power adaptive motor, and combined the different pole arc coefficients, analysis results showed that the reducing of cogging torque was about 35%. Then, unequal pole arc coefficients were globally optimized by the global optimization algorithm, showed that the cogging torque was further optimized. Finally, the prototype was produced on the basis of the results of theoretical research and given a prototype test, the results showed that: compared to the cogging torque measured data and the results of optimization, the overall error was about 5%, and the overall trend curve matches the optimization. Therefore, in this paper the method of weakening cogging torque of the power adaptive motor was effective and feasible.