During the Mesozoic, eastern China experienced a significant tectonic regime transition from the Paleo- Asian to the Paleo- Pacific domains, marked by a shift in tectonic trends from an approximately E- W to NE and NNE orientation. This transition was accompanied by large- scale magmatism, tectonic deformation, sedimentation, and basin formation, providing an ideal natural laboratory to investigate crust- mantle interactions and the dynamic mechanisms underlying tectonic regime transformations. This paper presents a brief analysis of multidisciplinary studies related to Mesozoic tectonic deformation, magmatism, and deep structures in the North China region of eastern China. By analyzing tectonic features in North China and the broader eastern region, the study explores the crust- mantle decoupling mechanisms involved in the transition from the Paleo- Asian to the Paleo- Pacific tectonic framework. Our findings suggest that the tectonic regime transition in eastern China initiated in the Middle to Late Jurassic. During this period, numerous syntectonic granitoid plutons formed, extending from the continental margin of the Liaodong Peninsula to inland regions of North China. Concurrently, the middle to upper crust experienced SE- NW compression, resulting in the development of faults, folds, and ductile shear zones in various zones. However, the orientation of metamorphic schists and other structures in the deep cratonic basement remained unchanged, indicating the presence of detachment zones between the basement and overlying strata. This detachment, combined with syn- tectonic magmatic flow in the lower crust, manifested as crustal interlayer detachment and decoupling of the crust. Simultaneously, the upwelling of mantle material induced partial melting of the lower crust and potentially facilitated horizontal flow of mantle material from east to west. These processes disrupted the original crust- mantle equilibrium, leading to crust- mantle material decoupling.