The no-load back electromotive force (EMF), air-gap flux density, cogging torque and the other performances of the outer rotor permanent magnet synchronous motor (PMSM) solved and calculated which based on the global analytical method. The analytical calculated results are in good agreement with those calculated by the finite element method, which verifies the accuracy of the global analytical method for solving the outer rotor PMSM. On this basis, the second-generation non-dominated sorting genetic algorithm (NSGA-Ⅱ) is used to optimize the multiple structural parameters and performance of the motor with multiple objectives. Compared with the original method, the overall performance of the optimized motor has been effectively improved. The simulation as well as experimental verification proves the reasonable validity of the proposed method.