From Han dynasty on, traffic lines located in southern Tarim basin had been changed under the influence of natural and human environment vicissitudes. On the base of the long time investigation and study of the ancient ruins scattered in the south Takalimakan desert including the analysis results of the deposit section, the historical document, as well as the archaeological studying results, the research showed that during the Han dynasty and Tang dynasty, all natural and human conditions provided a helpful supporting environment foundation to regional development. Indicators of ancient relics and sedimentary layers showed that the southern Tarim basin was in a relatively wetter climate during Han dynasty and Tang dynasty, which was useful for irrigation agriculture and economic development. The oases countries, controlled by the central power of China, were in the stage of administrative management stable, society maintenance, and communication with each other frequent; as a result, roads connecting the oases of south Tarim basin were maintained and unblocked.
After those two dynasties, roads experienced much more vicissitudes because human and natural environment of the basin became unhelpful to oases development, society were in chaos for countries of oases in Tarim basin scrambling for the power, which made wars broken frequently, irrigation system of oases destroyed, and oases deserted. The sedimentary layers of south Tarim basin analysis indicated that the first desert layer appeared in about 1500B.C. because the climate of Tarim basin turned warmer and drier during Wei-Jin dynasty, and the same feature emerged during Song-Yuan dynasty, it enhanced the ancient oases of south Tarim Basin to be deserted further. The new oases were developed near to the upper reaches of rivers more, and roads connecting the west to east locating along south Tarim basin were also moved from north to south.