The invention relates to a traction motor, more particularly, to a single bearing structured heavy-duty locomotive traction motor. The invention aims to solve the unreasonable connection structure between the rotor shaft driving end and the power input shaft of the gear box of a single bearing structured heavy-duty locomotive traction motor in prior art and to solve the problem that the bearing can not be replaced online. The rotor shaft driving end of the single bearing structured heavy-duty locomotive traction motor is connected with a coupling shaft in a column shape; the coupling shaft is provided with threaded through holes along the axis line of the columnar coupling shaft, and one end face of the coupling shaft is provided with meshing teeth. The driving end face of the rotor shaft is provided with a fixing hole, and the axis of the fixing hole coincides with the axis of the rotor shaft. One end of the non-engaging tooth of the coupling shaft is inserted into the fixing hole with interference fit. According to the invention, it is possible to meet the application requirement of a 30 ton axle-weight locomotive, and to realize the function of replacing the bearing without unloading the locomotive. Therefore, the repair time and cost for locomotive traction motor faults are greatly reduced while the punctuality rate and utilization rate of the locomotive are improved.