The wellbore integrity failure caused by high-temperature thermal injection has drawn widespread attention in thermal recovery wells for heavy oil. This study establishes a temperature calculation model for the wellbore of heavy oil thermal recovery wells with complex multi-layer casing-cement sheath structures, taking Well X in the Bohai oilfield as a case study for calculating and analyzing the wellbore temperature field. The model's computational results closely matched the field-measured data from the well, validating its accuracy and applicability. Based on this, the paper discusses in detail the effects of thermal insulation performance of the tubing, injection temperature, injection rate, and injection duration on the wellbore temperature distribution. The results indicate that reduced thermal insulation performance of the tubing significantly elevates temperatures at the outer walls of both the insulated tubing and production casing. The combined use of Class E aerogel-insulated tubing and annular nitrogen injection effectively prevents outward heat transfer from high-temperature fluids within the tubing. This research provides a theoretical foundation for predicting wellbore temperatures in heavy oil thermal recovery wells and holds significant implications for enhancing both safety and economic efficiency in thermal oilfield development.