An electric excitation permanent magnet switch, an electric excitation permanent magnet switch reluctance motor and an excitation method. The two magnetic poles of a permanent magnet (12) of a permanent magnet switch and the two ends of an iron core wound with an excitation coil (11) are connected to each other separately via two soft magnets (12), with the soft magnet having a salient pole (14,15) provided thereon. A motor uses the permanent magnet switch as the basic component of the stator and rotor, with two magnetic salient poles of each component being arranged axially, wherein the salient pole of the stator component and that of the rotor component are arranged in an opposite manner with an air gap, the excitation coil of the stator component and the rotor component at the symmetric axis position is taken as a phase line to access an excitation control power supply after serial connection or parallel connection. Electric excitation is carried out on the combined motor formed by shaft connection and rotation dislocation among single motors and the stator component in a bi-phase way simultaneously. The electric excitation permanent magnet switch and electric excitation permanent magnet switch reluctance motor are energy-saving, low in magnetic loss and high in magnetic efficiency, which use the combined motor and bi-phase electric excitation, realizing small subdivision stepping angle and improving operation stability, control precision and output power.