Abstract: The cryogenic motor is the key component of asubmerged liquefied natural gas（LNG） pump, and the optimization design of stator flow ducts has a direct impact not only on the motor cooling performance, but the pump working performance. The design process of flow ducts of 15 k W submerged LNG pump cryogenic motor was studied. Based on the calculation idea of traditional teeth-yoke magnetic potential, the calculation method of square stator yoke magnetic potential was given, and then the impacts of stator edge distances and flow holes widths on motor yoke magnetic potential and air gap flux density were discussed by finite element analysis（FEA）. The change rules of motor yoke magnetic potential and air gap flux density with different stator flow ducts were obtained, and they will provide reference for the design of submerged LNG pump cryogenic motor.