A new 3-DOF deflection type PM motor with a "butterfly" type rotor is proposed in this paper. In order to overcome the disadvantages of torque characteristics of the single layer structured permanent magnet 3-DOF motor mentioned in the previous research, the air-gap magnetic field and electromagnetic torque of the motor are analytically modeled using the seperation of variables method and the Lorentz force method in spherical coordinates. The space-harmonics of the magnetic field and the influence of structural parameters on the fundamental flux density and torque amplitude are defined; also the 3D finite element simulation and analysis are performed simutaneously. In the present study, the distribution characteristics and the regularities of air gap magnetic field, spin and deflection torque are investigated under different calculation methods. Simulation results show that the flux density distribution and torque characteristics with "butterfly" type permanent magnet rotor structure is superior to single layer structure. The spacial distribution of radial component of the flux density approximates the flat top waves and its maximum magnitude values appear in the middle layer of the rotor poles. The computation errors by the analytical and finite element methods are all less than 6.7%.