The Jinxi Flexural Belt represents an important tectonic unit in the central North China Craton, whose sedimentary and structural evolution is closely linked to the overall tectonic development of the craton. Based on carbonate core samples obtained from the Daning and Yonggu wells, this study applies clumped isotope (Δ??) thermometry to quantitatively constrain the burial temperatures and diagenetic fluid characteristics, and to explore the coupling mechanisms between stratigraphic hiatuses and the region’s thermal evolution. The clumped isotope data reveal that matrix carbonates (average 42.27 °C) record integrated signals of low-temperature sedimentation and subsequent burial heating, whereas calcite veins (average 106.2 °C) reflect later exogenic fluid activities. High-temperature solid-state reordering models indicate that several samples experienced multiple thermal events from the Jurassic to the Quaternary, during which burial temperatures rose to approximately 110 °C. Integrating clumped isotope evidence with regional thermal history and diagenetic evolution, this study reconstructs the thermal burial history of the Jinxi Flexural Belt and constrains the maximum burial temperatures to 110 °C in Daning and 100 °C in Yonggu. Furthermore, the calcite veins in the Daning Majiagou Formation and Yonggu Cambrian strata are interpreted to have formed during Yanshanian and Himalayan hydrothermal events, respectively. These findings suggest that intense tectonic deformation during these periods led to large-scale folding and thrust faulting, establishing the regional flexural structural framework of the Jinxi Belt.