Abstract: Accurate prediction of the maximum circulating temperature distribution during cementing operations is a critical prerequisite for optimizing cement slurry performance, mitigating operational risks, and improving well cementing quality. A transient multi-regional wellbore heat transfer model for sequential multi-fluid injection is established based on fluid volume displacement and coupled wellbore–formation heat transfer mechanisms. The governing equations are solved using a fully implicit finite difference method, and a dynamic analytical framework for determining the maximum temperatures of lead and tail slurries is developed by incorporating a density–temperature mapping relationship. The results indicate that, under the combined effects of fluid thermophysical properties and injection parameters, the wellbore temperature field exhibits strongly nonlinear evolution. The temperature peak is not fixed at the bottomhole; instead, it progressively shifts upward during fluid circulation. Specifically, the maximum temperatures of both the lead and tail slurries occur in the middle-to-lower sections of the wellbore. After the lead slurry reaches the bottomhole, the bottomhole temperature decreases rapidly, accompanied by enhanced heat exchange. Meanwhile, the temperature at the wellhead experiences a pronounced decline during the early stage of cementing, followed by a gradual recovery until thermal equilibrium is achieved. The proposed model enables accurate prediction of wellbore temperature under dynamic displacement conditions during cementing. It provides a robust theoretical basis and technical support for rational design of slurry thickening time, optimization of slurry formulations, and scientific determination of operational parameters, demonstrating significant engineering application value.