Recent studies reveal that human occupation of the Tibetan Plateau is much older than we thought, since the late Middle Pleistocene. During the past 200 ka years, Denisovans and modern human successively occupied or even overlapped for several thousand years in some parts of the plateau. The northeastern Tibetan Plateau is the place where the majority prehistoric archaeological sites found on the plateau, thus providing richest information about how human first spread to the plateau and how they adapted to the high-elevation environment. Studies in Baishiya Karst Cave site suggest that Denisovans occupied this region from around 200 ka to about 30 ka. In the late Denisovan occupation period, traces of modern human started to appear in the southern plateau. In the northeastern plateau, some new sites dated to 40-20 ka have been found, but still hard to say which human species the inhabitants were. From 15 to 6 ka, microblade populations intensively occupied the eastern and southern part of plateau. So far, the earliest microblade sites on the plateau were found in the northeastern plateau, indicating that microblade populations spread from the North China through the northeastern margins of the plateau. Our recent excavations and multidisciplinary studies in many Paleolithic and Epiplaleolithic sites in the northeastern Tibetan Plateau provides more new information on the early human occupation of and adaptation to the Third Pole on the earth.