The invention provides a stator shaft inner cooling pipeline structure which is used for cooling an external rotor wheel hub motor. The structure comprises a motor stator, a stator shaft, a cooling water pipe and an shaft inner cooling pipeline, wherein motor cooling liquid enters a cooling pipeline which is built in the stator shaft through the cooling water pipe; the shaft inner cooling pipeline is axially distributed along the motor shaft and is communicated with two ends of the motor shaft to form a pipeline loop; the cooling liquid flows out of a motor shaft through a water outlet pipe and is capable of taking away various types of loss in the motor operating process through convection heat transfer effect among the cooling liquid, the cooling water channel surface of the motor stator shaft and the inner surface of the motor stator, so that the purpose of cooling the external rotor motor is achieved.