The surface-mounted and interior permanent magnet synchronous motor(SIPMSM) has the characteristics of multiple variables, strong coupling and nonlinearity. In order to improve the performance of SIPMSM, this paper presents a multi-objective optimal design process using Taguchi and response surface methodology(RSM). The peak value of cogging torque(PVCT), ratio value of average torque and permanent magnet weight(RTW), torque ripple and back-EMF total harmonics distortion(ETHD) are selected as optimization goals. The experiment matrix is established by Taguchi method, and analyzed the tendency and proportion of the effect of the optimization parameters on SIPMSM performance. The rules of choosing multi-objective optimization parameters are obtained. The least-squares method is used to establish the optimal objective function, and RSM is used to obtain the resolutions of the optimization objective function. Comparing the initial performance with optimized performance verifies the effectiveness of the proposed method.