To date, electric vehicle technologies have become research hotspots of automotive companies and research institutes due to global energy crisis. Permanent magnet synchronous motor has become the first choice for electric vehicle drive motor, owing to excellent efficiency and high power density. Structural selection of drive motor for various electric vehicles has become one of the key issues in matching of electric vehicle power system. This paper starts from the establishment of motor coupling simulation model employing FEM, matlab and simulink. Then, based on the control strategies of id = 0, MPTA and weak field, external characteristics of three motors with various rotors are explained. Subsequently, with adoption of genetic algorithm, the parameters of three motors with different rotor structures are optimized taking the same volume of permanent magnet as constraint condition, the maximum output torque and the smaller torque ripple as optimization targets. Besides, the parameters including crossed inductance, direct axis inductance, permanent magnet torque, reluctance torque, iron loss, eddy current loss and torque ripple are compared and analyzed, which provides theoretical guidance for the selection of electric vehicle driving motors.