The Longmu Co—Shuanghu—Lancang River suture zone, a plate boundary between Gondwanaland and Eurasia plates during the period from the Carboniferous to the Permian, was reported by myself at first time in 1987 and has been as the key point for research the tectonic setting in the Qinghai—Xizang (Tibet) plateau in the past twenty years. The mystic veiling of this plateau was discovered in recent years due to abundant researth data, including the specifically geological research, 1∶250000 regional geological mapping has been completed in Qiangtang area, and the third edition geological map of the Qinghai—Xizang (Tibet) plateau has been published. In this paper, we will review the research history, divergence and progress of the Longmu Co—Shuanghu—Lancang River suture zone and the Northern part of the Gondwanaland. We will also summarize the geological differences between the two sides of the Longmu Co—Shuanghu—Lancang River suture zone, according to their basement character and compositions, Paleozoic sedimentary formations, biogeographic provinces, ophiolites, high pressure metamorphic belts, magamatic activitis, metamorphism, tectonic movements, and physical characters. These results suggest that the Longmu Co—Shuanghu—Lancang River suture zone is a significant portion for understanding the geological evolution of the Qinghai—Xizang(Tibet) Plateau, and all the results will provide important information for detailed research in the Qinghai—Xizang(Tibet) Plateau.