In this paper a novel magnetic field modulation linear primary permanent magnet synchronous motor (LPPMSM) is proposed, which is originated from brushless electrically excited synchronous machine ( BEESM ) .LPPMSM have short primary (rotor side), long secondary structure. The primary side consists of an iron core with salient teeth wound which 3-phase armature windings and permanent magnets (PMs) mounted on the surface of stator teeth, and second side only combined by magnetic barrier. The three-phase AC armature windings and PMs have different number of poles, when the motor is operated with steady-state, the armature windings form a traveling magnetic field in the air gap of the motor, and a constant static magnetic field generated by permanent magnets. The two magnetic field are modulated by secondary magnetic barrier, which bring out indirect coupling, and the electromagnetic torque formed in the rotor. In the city rail transit drive motor application, this novel magnetic field modulation LPPMSM compared with the traditional linear synchronous motor, the dosage of armature windings or permanent magnets can be reduced, and the secondary structure is simple and reliable, which saves material cost and maintenance cost; compared with the traditional linear motor, it can improve the efficiency and power factor of motor. This paper introduces the structure characteristics and operation mechanism of this kind of motor, LPPMSM with a 12+8 pole was designed. The effect of pole-arc coefficient and salient pole height on coupling capacity of magnetic barrier was researched, and the values of pole-arc coefficient and salient pole height were obtained. The Maxwell-2D model was established and no-load operation was analyzed by the finite element analysis (FEA), the flux plot, the flux density and no-loud EMF were obtained. The results prove the feasibility of the design of LPPMSM.