A permanent magnet motor rotor, comprising a rotor core, the permanent magnet motor rotor further comprises: tangentially magnetized main-pole permanent magnets, the main-pole permanent magnets being disposed in a radial direction of the rotor core, number of the main-pole permanent magnets being equal to number of poles of the permanent magnet motor rotor, the main-pole permanent magnets being uniformly arranged in a circumferential direction of the rotor core, and closest surfaces of any two adjacent main-pole permanent magnets having same magnetic pole, wherein an N-pole of each main-pole permanent magnet faces an N-pole of an adjacent main-pole permanent magnet, and an S-pole of each main-pole permanent magnet faces an S-pole of the other adjacent main-pole permanent magnet; tangentially magnetized auxiliary permanent magnets, the auxiliary permanent magnets being disposed in the radial direction of the rotor core, and the auxiliary permanent magnets each being located between any two adjacent main-pole permanent magnets and uniformly distributed around a circumference of the rotor core; wherein each of the auxiliary permanent magnets, which is interposed between the S-poles of two adjacent main-pole permanent magnets, has following characteristic: an N-pole of the auxiliary permanent magnet faces an S-pole of one adjacent main-pole permanent magnet, and an S-pole of the auxiliary permanent magnet faces the S-pole of the other adjacent main-pole permanent magnet; wherein each of the auxiliary permanent magnets, which is interposed between the N-poles of two adjacent main-pole permanent magnets, has following characteristic: an N-pole of the auxiliary permanent magnet faces the N-pole of one adjacent main-pole permanent magnet, and an S-pole of the auxiliary permanent magnet faces the N-pole of the other adjacent main-pole permanent magnet; each of the auxiliary permanent magnets is located at a position offset from a symmetrical centerline between any two adjacent main-pole permanent magnets, and each auxiliary permanent magnet is offset toward an adjacent main-pole permanent magnet having an opposite magnetic pole from that of the auxiliary permanent magnet; wherein coercivity of the auxiliary permanent magnets is less than coercivity of the main-pole permanent magnets; and number of the auxiliary permanent magnets is equal to the number of the main-pole permanent magnets. tangentially magnetized main-pole permanent magnets, the main-pole permanent magnets being disposed in a radial direction of the rotor core, number of the main-pole permanent magnets being equal to number of poles of the permanent magnet motor rotor, the main-pole permanent magnets being uniformly arranged in a circumferential direction of the rotor core, and closest surfaces of any two adjacent main-pole permanent magnets having same magnetic pole, wherein an N-pole of each main-pole permanent magnet faces an N-pole of an adjacent main-pole permanent magnet, and an S-pole of each main-pole permanent magnet faces an S-pole of the other adjacent main-pole permanent magnet; tangentially magnetized auxiliary permanent magnets, the auxiliary permanent magnets being disposed in the radial direction of the rotor core, and the auxiliary permanent magnets each being located between any two adjacent main-pole permanent magnets and uniformly distributed around a circumference of the rotor core; wherein each of the auxiliary permanent magnets, which is interposed between the S-poles of two adjacent main-pole permanent magnets, has following characteristic: an N-pole of the auxiliary permanent magnet faces an S-pole of one adjacent main-pole permanent magnet, and an S-pole of the auxiliary permanent magnet faces the S-pole of the other adjacent main-pole permanent magnet; wherein each of the auxiliary permanent magnets, which is interposed between the N-poles of two adjacent main-pole permanent magnets, has following characteristic: an N-pole of the auxiliary permanent magnet faces the N-pole of one adjacent main-pole permanent magnet, and an S-pole of the auxiliary permanent magnet faces the N-pole of the other adjacent main-pole permanent magnet; each of the auxiliary permanent magnets is located at a position offset from a symmetrical centerline between any two adjacent main-pole permanent magnets, and each auxiliary permanent magnet is offset toward an adjacent main-pole permanent magnet having an opposite magnetic pole from that of the auxiliary permanent magnet; wherein coercivity of the auxiliary permanent magnets is less than coercivity of the main-pole permanent magnets; and number of the auxiliary permanent magnets is equal to the number of the main-pole permanent magnets.