The invention relates to a rodless oil extraction 
system driven by an underground rotation motor and applied to the technical field of oil extraction in oil fields. The rodless oil extraction 
system comprises a 
pressure balance device, a three-phase asynchronous rotation motor, a mechanical transformation mechanism, a lower cylinder tube and a lower stopper. A balance 
piston and an upper spacing ring are arranged in an upper cylinder tube, a ventilation hole is arranged on the wall of the upper cylinder tube, the lower end of the upper cylinder tube is fixedly provided with the three-phase asynchronous rotation motor, the center of a 
motor shaft is provided with an axial through hole, the lower end of the three-phase asynchronous rotation motor is fixedly provided with the lower cylinder tube and the lower stopper, the mechanical transformation mechanism is arranged in the lower cylinder tube and comprises a shaft 
coupling, a lead screw and a nut, the upper end of the shaft 
coupling is connected with the 
motor shaft, the lower end of the shaft 
coupling is connected with the nut, and the lower end of the lead screw penetrates through a center hole of the lower stopper. The 
motor shaft drives the nut to rotate by the shaft coupling, the lead screw makes a linear 
reciprocating motion under the drive of the nut, and an oil pumping pump is driven to realize lifting oil pumping. The rodless oil extraction 
system driven by the underground rotation motor solves the problem of lopsided wear of a rod 
pipe existing in a 
directional well, enhances the efficiency of the oil pumping pump and lowers the 
energy consumption.