The invention discloses a magnetic field modulation type linear motor. The magnetic field modulation type linear motor comprises a primary body and two secondary bodies. The two secondary bodies are in a C-shaped mirror image arrangement, and the three surfaces of the inner side of the C shape are provided with secondary grooves and secondary teeth at equal intervals, and three surfaces of air gaps are arranged among the primary body and the secondary bodies. The primary body comprises two same primary iron cores and a connecting beam used for connecting the two primary iron cores. The upper surfaces and the lower surfaces of the primary iron cores, and the surfaces of the primary iron cores back to the connecting beam are provided with salient pole teeth, which are the same teeth, and are arranged at equal intervals, and are provided with armature windings in a coiled manner. The adjacent armature windings are connected together in an end-to-end manner, and the armature winding direction of the salient pole teeth of the upper surface is opposite to the armature winding direction of the salient pole teeth of the lower surface, and the armature winding direction of the salient pole teeth of the surface back to the connecting beam is the same as the armature winding direction of the salient pole teeth of the lower surface, and the armature windings of the salient pole teeth of the three surfaces are serially connected together to form a one-phase winding. The ends of the salient pole teeth close to the air gaps are provided with permanent magnets.