Studies have shown that the western Indosinian “Bayan Har-North Qiangtang-South Qiangtang-Lasha” orogenic belts were formed in the Paleo-Tethys setting of multi-ocean basins, multi-terrains and multi-island arcs. The Songpan-Ganzi and South Qinling orogenic belts located above the Yangtze passive margin show large-scale deep decollement orogenic mechanism between the Upper Proterozoic metamorphic basement and Paleozoic-Triassic covers, as well as intensive shear strain of the Yangtze upper crust. The deep subduction (>100 km) of the Yangtze crust and root extrusion mechanism yielded large-scale high pressure/ultra-high pressure metamorphic belts exposed in the Dabie-Sulu orogenic belt.