To settle high rotating speed of hollow shaft in the high speed-bogie and sustain the big driving and retarding torque and the small structure space in the connection point etc, we take the choice of using end tooth construction. When we compared with strait tooth disc, we can find that the arc tooth end tooth disc can increase the hardness of contact of tooth flanks and the root of tooth thus to meet the performance requirement of the coupling from the drive system of high-power haulage motor as well as to prolong life-span of end tooth disc. The arc end tooth coupling is a coupling with special construction which has been widely used in the rotor structure of Europe and American aero- engine in the modern times. The coupling in the haulage motor mainly contact with the electric machine rotor and gear transfer system in the mean while deliver the torque of the electric machine. According to the high speed and heavy loading development of the railway there will be more and more requirements from the high power drive system to the carrying capacity of the coupling end-tooth.