Modern humans have inhabited almost all geographical regions of Eurasia after their dispersal around 60,000-50,000 years ago. Such success has generated heated discussions regarding the dispersal and adaptation processes that are still not well reconstructed. In the eastern Eurasian Steppe, the earliest evidence for modern human expansion into the region, dating back as early as 48-45 thousand years ago, is associated with a specific blade technology known as the Initial Upper Paleolithic (IUP). However, in the southern East Asia, a different kind of stone tool industry known as core and flake technology, predominates the regional archaeological records for most of the Pleistocene, disrupted by a few small-scale and temperate variations, such as the potential expansion of the IUP-like technology into what is today North China. The development of lithic technologies in these regions during this pivotal period of these regions raises important questions about the emergence of modern humans and their behavioral patterns in the area: When did early modern humans first arrive in East Asia? How did hunter-gatherers adapt to the diverse landscapes in eastern Asia during this dispersal? What were the relationships between the different technological traditions in eastern Asia? Given the challenging environment of the Tibetan Plateau, how and why did early modern humans expand and adapt to the high-elevation environments? In my dissertation, I employed technological analysis of the stone tool assemblages from North Mongolia, North China, and the Tibetan Plateau. In conjunction with GIS modeling of climatic data and site distributions, but also integrating recent discoveries in genetic and physical anthropology, I investigated the key issues listed above. My results suggest that rare examples of blade assemblage such as the Dwya Devu site on the Tibetan Plateau, and the Shuidonggou site in North China, are likely to be the testimonies of a southward dispersal of human populations from the eastern Eurasian Steppe. Owing to the lack of technological ancestry in East Asia, blade technology in East Asia could be sourced to the technocomplexes represented by the Initial Upper Paleolithic industry or successive younger laminar assemblages in the Steppe belt. The latter are recognized as evidence for a northern, inland route for Homo sapiens dispersal into North Asia. The appearance of blade technology in the Tibetan Plateau and North China, however, appears to be a short episode, quickly followed by a ‘reversal’ back to core and flake technology. I suggest that blade technology and the associated subsistence strategies were part of a suite of behavioral adaptations that increase human fitness in the cold habitats of the Steppe belt. In other words, the introduction of blade technology from the Steppe prompted the adaptability of human groups to settle in the similar environmental pressures in the Tibetan Plateau, such as cold, dry, strong seasonality, open grassland landscapes, compared to the core and flake technology that is more widely used in temperate lowlands. Technological shifts such as the introduction of blade technology and its disappearance in East Asia during Marine Isotope Stage 3, may be indicative of human population movements and adaptative responses under varied environmental conditions. In this sense, my dissertation work informs on the migrations and adaptations of Homo sapiens in the diverse landscapes of the eastern part of Asia including the Steppe belt, the high altitudes of the Tibetan Plateau, and lowland temperate East Asia.