A low-cost permanent-magnet brushless direct-current motor for an electric vehicle is characterized by comprising a stator iron core, stator windings, a shaft, a rotor iron core, permanent steel magnets, fake electrodes and the like. The fake electrodes made of convex soft iron and the permanent steel magnets are arranged at intervals and adhered on the rotor iron core to form a pair of electrodes, the magnetic field directions of the permanent steel magnets are consistent and all face the inner side or the outer side of a rotor. The arc length of the permanent steel magnets is approximately 0.4 times of that of the electrodes. The arc length of the fake electrodes attached to one side of the rotor iron core is the difference between the arc length of the paired electrodes and that of the permanent steel magnets, and the arc length of the fake electrodes close to one side of the stator iron core is equal to that of the permanent steel magnets, that is, the arc length of the protruding part of the convex fake electrodes is approximately 0.4 times of that of the paired electrodes, and the thickness of the protruding part of the fake electrodes is equal to that of the permanent steel magnets. The fake electrodes are in central symmetry, and the thin part of the fake electrodes on two sides is one third of that of the permanent steel magnets. Though torque is reduced by 10%, magnet steel usage is reduced by 40%, and cost is reduced by approximate 17%.