The invention relates to electromotor, in particular to three-phase alternating current permanent magnet planet rotor magnetic resistance electromotor. The invention can solve the problem that low-speed motor which can directly output high torque is scarce. The electromotor comprises a case, a stator assembly, a rotor assembly and an end cap arranged at the two ends of the case; wherein the stator assembly is composed of a stator ring fixed in the case, 6M stator magnetic poles fixed on the stator ring and central windings wound on the stator magnetic poles; the rotor assembly comprises N planet spindles, the two ends of the planet spindle are provided with a planet support, the two ends of each planet spindle are supported on the planet support by a bearing, each planet spindle is fixed with a planet rotor and a planet gear, the planet rotor is composed of a rotor ring, a rotor magnetic pole fixed on the rotor ring and a permanent magnet fixed on the rotor magnetic pole, and the pitch of the rotor magnetic pole is equal to the pitch of the stator magnetic pole. The electromotor of the invention can be applied to all occasions requiring low-speed and high-torque load.