The design of fault tolerant motor was studied in order to minimize the volume and weight of direct drive electromechanical actuator, and to improve the fault tolerant and reliability. The design requirements of fault tolerant motor were analyzed, and a three-phase twenty-four-slot twenty-pole surface permanent magnet synchronous motor was designed to meet the requirements. The parameters of the motor were optimized. The finite element model of the motor was established to simulate a single phase short circuit or open circuit fault. The simulation results show that the motor has a perfect property in the magnetic isolation and fault tolerant, and can meet the fault tolerant requirements of direct drive electromechanical actuator.