The invention provides a downhole sampling device for thickened oil. An in-well fluid sample is contained in a sample barrel, a sample inlet hole is axially formed in a head end connector, an inner center hole is axially formed in a control pup joint, four sample inlets are laterally formed in the control pup joint, a lead screw is installed on the upper segment of the inner center hole in the control pup joint, a sealing plunger piston is installed on the lower segment, the upper end of the lead screw is connected to a micro motor, the micro motor drives the lead screw to rotate in the forward direction or the backward direction under control of a circuit module to drive the sealing plunger piston to move vertically, when the lead screw rotates in the forward direction, the sealing plunger piston moves upwards to a limited position, the lower end face of the sealing plunger piston is away from the upper end face of the sample inlet hole, at the moment, the fluid sample passes throughthe four sample inlets and the sample inlet hole and enters an inner cavity of the sample barrel, and when the lead screw rotates in the backward direction, the sealing plunger piston moves downwardsto a limited position to seal the fluid sample in the sample barrel. The downhole sampling device for the thickened oil is novel in principle, unique in structure, stable in work, easy to operate, lowin machining difficulty and cost, safe, environmentally friendly and remarkable in benefit.