Abstract:The Asian interior is the largest mid-latitude arid zone in the Northern Hemisphere, being different from the other arid areas controlled by the Subtropical High. The present Asian mid-latitude situates in the heart of the Eurasia, being far away from any of the ocean's moisture sources. How exactly does the mid-latitude Asia become a vast arid area? What kinds of arid processes have been experienced? How is about the mechanism of its formation and evolution? All these issues are unsolved questions. Actually, the present desert environment of the mid-latitude Asia is not a result of short time evolution, but that of long-term stepwise aridification processes. The collision between the Africa Plate, Arabian Plate, and Indian Plate with the Eurasian Plate, the uplift of the Tibetan Plateau, the shrinkage of the Neotethys, and the eustatic global sea-level decline driving by Cenozoic global cooling have all involved in the aridification processes. The mid-latitude experienced Eocene sub-humid, Oligocene sub-humid to semi-arid, and the arid to extreme arid climate since the latest Miocene.