This paper deals with the comparative investigation on the electromagnetic field characteristics of interior permanent magnet synchronous motors (IPMSMs) based on finite element method. With identical magnetic structure, this paper proposes newly designed PM magnetization patterns for the cogging torque reduction. Based on this method, in spite of the longer stack length of the rotor and stator core, the torque characteristics can be much more improved in comparison with the conventional model. Along with the torque characteristics, the performance evaluation is also addressed based on the analyzed power loss values.