The invention relates to an offshore thickened oil thermal recovery wellhead lifting monitoring device. The offshore thickened oil thermal recovery wellhead lifting monitoring device comprises a barrel-shaped body with the sealed upper end and the open lower end, a plurality of sealing rings embedded in the body at intervals, a tubular oil pipe stretching compensator penetrating through the body axially, a sleeve pipe arranged outside the oil pipe stretching compensator in a sleeved mode, a spring device connected with the upper end of the sleeve pipe through a spring base, a stress sensor installed at the upper end of the spring device and a computer display system electrically connected with the stress sensor, wherein annular reserved space exists between the oil pipe stretching compensator and the body, the outer wall of the sleeve pipe makes contact with the sealing rings in the body, a gap is reserved between the inner wall of the sleeve pipe and the oil pipe stretching compensator, the upper end and the lower end of the body are respectively provided with a flange structure, and the monitoring device is fixed between an oil pipe head and a sleeve pipe head through the flange structures at the upper end and the lower end of the body. In the thickened oil thermal recovery process, the offshore thickened oil thermal recovery wellhead lifting monitoring device can avoid lifting of a Christmas tree caused by extending of the sleeve pipe, guarantee normally operation of oil recovery, effectively monitor the extending quantity of the sleeve pipe in time, provide guidance for operation and lower operation risks.