A set of the Early Carboniferous-Early Permian ophiolitic melanges, unconformably overlain by the Late Permian-Early Triassic beach-subfacies quartzose sandstones, is first discovered in Hoh Xil region, Qinghai Province in 1990, which indicates that Paleotethys existed in the Early Carboniferous-Early Permian. The ocean crust began to subduct beneath the North China Block in Kunlun in the Late Carboniferous, marked by the beginning of Arc-type magrnatic activity and by formation of an arctrench system. At the end of the Early Permian the North Qiangtang Block weakly collided with the southern margin of the North China Block, which is demonstrated by a wide(>100km) preserved accretionary wedge. A land connection established between the North China Block and the North Qiangtang Block, which provided the Dicynodont a direct route from Indochina to Central Asia. The region was relatively stable during the Late Permian-Early Triassic. A thick(5—10km) flyschoid sequence was deposited in a trough during the Mid-Late Triassic. The strong orogenesis occurred during the end of the Triassic to the Early Jurassic. This resulted in the final close of the Paleotethys and the formation of the Indosinide. After this, intracontinental regime characterizes the Yanshanian and Himalayan tectonism. Since the Oligocene, the region has been uplifted as a whole, which resulted in the appearance of the plateau plain.