Abstract: Accurately predicting the maximum circulating temperature of cement slurry during the cementing process is a critical prerequisite for optimizing cement slurry performance, preventing operational risks, and enhancing cementing quality. To this end, based on the fluid volume displacement and wellbore-formation coupled heat transfer mechanisms, a multi-region transient heat transfer mathematical model for the wellbore under sequential injection of multiple fluids was established. The model was solved using the fully implicit finite difference method, and combined with a fluid density-temperature matrix mapping relationship, and a dynamic calculation and analysis model for the maximum temperatures of both the lead slurry and the tail slurry was constructed. The results indicated that under the combined effects of fluid thermophysical properties and injection parameters, the wellbore temperature field exhibited highly nonlinear evolution characteristics. The temperature peak did not remain fixed at the bottom hole but gradually migrated upward as the fluid circulated. Specifically, the maximum temperatures of both the lead slurry and the tail slurry occurred in the lower-middle section of the wellbore. After the lead slurry reached the bottom hole, the bottom-hole temperature dropped rapidly, and the heat exchange intensified significantly. Meanwhile, the temperature at the bell mouth experienced a notable decrease in the early stage of cementing, then gradually rebounded, and eventually approached thermal equilibrium. The model developed in this study achieved accurate prediction of wellbore temperature under dynamic displacement conditions during cementing, providing a reliable theoretical basis and technical support for reasonably setting cement slurry thickening time, optimizing slurry formulations, and scientifically determining operational parameters.