The invention relates to a multistage super-long oil-submersible screw pump system for thermal extraction of thickened oil. The system is mainly composed of a base, an energy-saving motor, a clutch, abearing body part, a cardan joint part, a rotor, a first coupling, a stator, a second coupling, a limiting short joint, a variable diameter coupling and a tail pipe. In the thickened oil extraction process, the clutch on the lower portion of the energy-saving motor transmits power to the cardan joint part, a cardan joint drives the rotor of an oil pumping pump, the rotor does eccentric motion ina rubber lining of the stator, a series of closed chambers are formed along the full length of the screw pump and the lining of the stator, when the rotor rotates, a medium is lifted to move from thesucking end to the discharging end in the axial direction, pressure is increased stage by stage, and the displacement is kept unchanged. The screw pump system is provided with a multistage super-longstructure, the range of the normal length-diameter ratio is exceeded, the machining technology of a special multistage super-long shaft is adopted, compared with a past screw pump, torque and output power are larger, the better oil extraction effect on the thickened oil is achieved, multiple times of thickened oil can be extracted within the same time, and the system is simple in structure and reliable in work.