Abstract:The Mesozoic Yanshan orogenic belt in the North China is typical of intracontinental orogeny, but there have been many divergent views on the dynamic mechanism of its orogeny for a long time. In this article an attempt is made to explore the key factors in the intracontinental orogeny by integrally looking into the structures in different depths of the lithosphere in order to discover the main characteristics of the Mesozoic tectonic movement in the Yanshan belt. At first, with the Jining-Chengde basement lithospheric fault belt as an example, activization of the preexisting weak structure belts is studied in terms of geological actions at different depth levels: (1) the surface faulted basins and their volcanic-sedimentary formations, (2) the different swells of block structures, (3) the rheological deformation and thermal activity, (4) the mantle-derived or crust-mantle miscible volcanism. Secondly, weakening of the lithosphere is investigated through the mantle-derived fusion-fluid metasomatism. In the end, with the tomographic imaging of the lithospheric structures is taken into account, it can be concluded that the upwelling of mantle diapir is the most important background of Mesozoic intracontinental orogeny in the North China Craton, and that the effects of interaction between adjacent plates should not be excluded. Finally, from comparison with other typical intracontinental orogenic belts abroad, it is further recognized that deep mantle materials upwelling and isostatic adjustment of upper lithosphere materials are essential differences of the intracontinental orogeny from the continental margin orogeny.