The cogging torque in stator permanent magnets of axial field fluxswitching permanent magnet motor (SPAFFSPM) is too large and with high noise due to the flux focusing. In order to reduce the cogging torque and improve the motors output performance, an analytic expression of the cogging torque of motor is deduced by energy perturbation method to analyze the parameters of stator and rotor structure. Based on the response surface methodology (RSM) and FEM, the response surface numerical model about stator slot width, rotor tooth inclination angle and shape factor of permanent magnet with cogging torque is obtained, then the optimal combination of the cogging torque with stator slot width, rotor tooth inclination angle and shape factor of permanent magnet is deduced. The accuracy of the analysis is examined by the 3D finite element and prototype of the experimental platform.